请你做出我上传题目的讲解视频。在视觉效果上我希望更适合中国小学三年级学生理解学习。并且希望可以通过视频让学生感觉到趣味从而提升兴趣。---(7) 芳芳用四个相同的长方形做拼图游戏,拼摆后图形的中间部分是个正方形。这个正方形的面积是 ( )。 [A] 70平方分米 [B] 81平方分米 [C] 280平方分米 [D] 361平方分米 **Chart/Diagram Description:** * Type: Geometric diagram showing the arrangement of four identical rectangles forming a larger square with a smaller square in the center. * Main Elements: * Four identical rectangles arranged around a central square. * The outer boundary forms a large square. * Dimensions are labeled outside the large square. A bracket indicates a length of 14 分米 horizontally across the top. A bracket indicates a length of 5 分米 vertically on the right side, corresponding to the shorter side of one rectangle. * Labels and Annotations: * "14 分米" is labeled horizontally above the top edge of the combined figure. * "5 分米" is labeled vertically to the right of the right edge of the combined figure, next to a vertical bracket indicating the dimension. * Relative Position and Direction: Four rectangles are placed around a central void, which forms a square. The longer side of each rectangle appears to be aligned with the side of the outer square, and the shorter side of each rectangle forms part of the side of the central square. The diagram shows two rectangles oriented horizontally and two oriented vertically. **Interpretation from diagram and problem statement:** The diagram shows that the outer shape is a large square formed by four identical rectangles surrounding a central square. The dimension 14 分米 represents the length of the longer side of one rectangle plus the length of the shorter side of one rectangle (or the side of the large square, if the arrangement implies this). Let's assume the longer side of a rectangle is 'L' and the shorter side is 'W'. The dimension 5 分米 represents the length of the shorter side of a rectangle. So, W = 5 分米. From the horizontal label (14 分米), it appears to represent the sum of the length and the width of one rectangle. This is because the top side of the outer square consists of the longer side of one horizontal rectangle and the shorter side of one vertical rectangle (when viewed from the top left corner to the top right corner, across the diagram's width). Or, looking at the top horizontal bar, its length is L. The length of the outer square is formed by L on the top. However, the 14分米 label is above the entire top edge. Let's re-examine the diagram. Let L be the length of the rectangle and W be the width of the rectangle. The diagram shows that the length of the outer square is L + W. The horizontal bracket labeled 14 分米 spans the entire width of the outer square. So, the side length of the outer square is 14 分米. Thus, L + W = 14. The vertical bracket labeled 5 分米 spans the width (shorter side) of one of the vertical rectangles. Thus, W = 5 分米. Substituting W = 5 into L + W = 14, we get L + 5 = 14, which means L = 14 - 5 = 9 分米. The central part is a square. The side length of this central square is the difference between the longer side and the shorter side of the rectangle, i.e., L - W. Side length of the central square = L - W = 9 分米 - 5 分米 = 4 分米. The area of the central square is (side length)^2. Area = (4 分米)^2 = 16 平方分米. Wait, the horizontal dimension 14 分米 seems to be labeled above the entire figure, suggesting the side length of the outer square is 14 分米. The vertical dimension 5 分米 is labeled next to the height of one rectangle's shorter side. If the side length of the outer square is 14 分米, and the side length of the outer square is also L + W, then L + W = 14. The vertical label 5 分米 is the width W of the rectangle. So W = 5. Then L = 14 - 5 = 9. The side of the inner square is L - W = 9 - 5 = 4. Area of inner square = 4 * 4 = 16. Let's reconsider the diagram. The 14 分米 label is above the entire width. The 5 分米 label is next to the height of the rectangle's shorter side. The diagram clearly shows that the side length of the large square is formed by the longer side of the rectangle plus the shorter side of the rectangle, i.e., L + W. So the side of the large square is 14 分米. Also, the shorter side of the rectangle is labeled as 5 分米. So W = 5 分米. Therefore, L + 5 = 14, which gives L = 9 分米. The side length of the central square is the difference between the longer side and the shorter side of the rectangle, which is L - W. Side length of central square = 9 - 5 = 4 分米. Area of central square = (4 分米)^2 = 16 平方分米. However, 16 平方分米 is not among the options. Let me re-examine the diagram and the problem description. The problem states that Fangfang uses four identical rectangles. The middle part is a square. Let the length of the rectangle be L and the width be W. Looking at the diagram again, the side length of the large square is L + W. The horizontal label 14 分米 is indeed the side length of the large square. So L + W = 14. The vertical label 5 分米 corresponds to the width of the rectangle, W. So W = 5. Then L = 14 - 5 = 9. The side length of the inner square is L - W = 9 - 5 = 4. The area of the inner square is 4 * 4 = 16. Let's assume the labels 14 and 5 represent different things. What else could they represent? Maybe 14 is the length L and 5 is the width W? If L=14 and W=5, then the side of the outer square is L+W = 14+5 = 19. The side of the inner square is L-W = 14-5 = 9. Area of inner square = 9 * 9 = 81. Let's check if this interpretation fits the diagram. If L=14 and W=5, then the longer side is 14 and the shorter side is 5. The outer square has side length L+W = 14+5 = 19. The diagram shows a dimension of 14 分米 above the entire width. This is likely the side length of the outer square. The diagram also shows a dimension of 5 分米 next to the shorter side of the rectangle. This is likely the width W. So, if the side length of the outer square is 14 分米, then L + W = 14. And W = 5 分米. This gives L = 9 分米. The side length of the central square is L - W = 9 - 5 = 4 分米. Area of central square = 4 * 4 = 16 平方分米. Let's consider another possibility for the meaning of the labels in the diagram. Perhaps 14 is the length L and 5 is the side of the inner square? No, 5 is clearly labeled next to the shorter side of the rectangle. Perhaps 14 is L and 5 is W. Then L=14, W=5. Side of inner square = L-W = 14-5 = 9. Area = 9*9 = 81. Side of outer square = L+W = 14+5 = 19. If the side of the outer square is 19, why is there a 14 label above it? Let's reconsider the first interpretation: Side of outer square = 14, W = 5. Then L = 9. Side of inner square = L-W = 9-5 = 4. Area = 16. Let's assume the diagram labels are intended to mean: The total width of the figure is 14 分米. The height of the shorter side of the rectangle is 5 分米. Since it's a square arrangement, the total height is also 14 分米. The side length of the outer square is 14 分米. Let L be the length and W be the width of the rectangle. From the diagram, the side length of the outer square is L + W. So L + W = 14. The width of the rectangle is labeled as 5 分米. So W = 5. Then L + 5 = 14, which gives L = 9. The side length of the central square is the difference between the length and the width of the rectangle, L - W. Side of central square = 9 - 5 = 4 分米. Area of central square = 4 * 4 = 16 平方分米. Still 16, which is not an option. Let me check the options again. 70, 81, 280, 361. Let me rethink the meaning of the diagram labels. Maybe the 14 is the length L and the 5 is the width W? If L = 14 and W = 5, then the side of the inner square is L - W = 14 - 5 = 9. The area of the inner square would be 9 * 9 = 81. Let's see if this fits the diagram. If L=14 and W=5, then the side of the outer square is L + W = 14 + 5 = 19. The diagram shows 14 above the outer square and 5 next to the shorter side. If L=14 and W=5, then the 14 should be the length of the longer side, and the 5 should be the length of the shorter side. The diagram shows the side of the outer square is made of one longer side and one shorter side (L+W). If L=14 and W=5, then the side of the outer square is 19. However, the label above is 14. This contradicts the assumption that L=14 and W=5. Let's go back to the first interpretation, where the side of the outer square is 14 and the width W is 5. Side of outer square = 14. Side of outer square = L + W. So L + W = 14. Width W = 5. L + 5 = 14. L = 9. Side of inner square = L - W = 9 - 5 = 4. Area of inner square = 4 * 4 = 16. Let's consider the possibility that the 14 is not the side of the outer square, but maybe the length of the longer side L. And 5 is the width W. If L = 14 and W = 5, then the side of the inner square is L - W = 14 - 5 = 9. The area of the inner square is 9 * 9 = 81. If L = 14 and W = 5, then the side of the outer square is L + W = 14 + 5 = 19. So, if the inner square area is 81, it implies L=14 and W=5. But the diagram shows the side of the outer square is labeled as 14. This is a contradiction. Let's re-examine the diagram very carefully. The horizontal bracket labeled 14 分米 spans the entire width of the outer square. So the side length of the outer square is 14 分米. The vertical bracket labeled 5 分米 spans the shorter side of one rectangle. So the width of the rectangle is 5 分米. Let L be the length of the rectangle and W be the width. So, the side of the outer square is L + W = 14. The width of the rectangle is W = 5. Substituting W = 5 into the equation, L + 5 = 14. L = 14 - 5 = 9. The side of the central square is the difference between the length and the width of the rectangle, which is L - W. Side of central square = 9 - 5 = 4. Area of central square = (side)^2 = 4 * 4 = 16. None of the options is 16. There might be an error in my interpretation or the options provided. Let's re-read the problem statement. "芳芳用四个相同的长方形做拼图游戏,拼摆后图形的中间部分是个正方形。这个正方形的面积是 (?)。" It confirms the setup. Let's double check the options: [A] 70 平方分米, [B] 81 平方分米, [C] 280 平方分米, [D] 361 平方分米. Option [B] is 81, which is 9 * 9. If the side of the inner square is 9, then L - W = 9. If the area of the inner square is 81, and the side length is 9, then L - W = 9. From the diagram, we know W = 5. So, L - 5 = 9, which means L = 9 + 5 = 14. If L = 14 and W = 5, then the side of the outer square is L + W = 14 + 5 = 19. However, the diagram labels the side of the outer square as 14. It seems there is a contradiction between the diagram labels and the options, assuming the standard interpretation of the diagram. Let's consider if the diagram labels mean something different. Possibility 1 (my initial interpretation): Side of outer square = 14, Width of rectangle = 5. Then L = 9, side of inner square = 4, area = 16. (Not in options) Possibility 2: Length of rectangle = 14, Width of rectangle = 5. Then side of inner square = 14-5 = 9, area = 81. Side of outer square = 14+5 = 19. (Area 81 is an option, but side of outer square is 19, labeled as 14 in diagram) Possibility 3: Maybe 14 is L+W and 5 is L-W? If L+W=14 and L-W=5, then adding the equations gives 2L=19, L=9.5. Subtracting the equations gives 2W=9, W=4.5. L=9.5, W=4.5. Inner square side = L-W = 9.5-4.5 = 5. Area = 25. Outer square side = L+W = 9.5+4.5 = 14. This fits the diagram labels! If the inner square side is 5, then the area is 25. (Not in options) Let's reconsider the possibility that the 14 is the length L and the 5 is the width W, and the label 14 above the outer square is a mistake, or perhaps it is meant to indicate L=14. If L = 14 and W = 5, then the side of the inner square is L - W = 14 - 5 = 9. The area of the inner square is 9 * 9 = 81. This result (81) is option [B]. Given that one of the options is 81, it is highly probable that the intended meaning was L=14 and W=5, and the diagram label of 14 above the outer square was incorrect (it should have been 19). Or, more likely, the 14 above the outer square represents L, and the 5 on the right represents W, and the side of the outer square is L+W, while the side of the inner square is L-W. In this case, L=14 and W=5. So, the side of the outer square is L+W = 14+5 = 19. The label 14 above it is confusing. However, if we assume L=14 and W=5 are the dimensions of the rectangle, then the side of the inner square is 14-5=9, and the area is 81. This is option [B]. Let's assume the diagram labels are correct as they are placed. The side of the outer square is 14. The width of the rectangle is 5. Side of outer square = 14. Side of outer square = L + W. So L + W = 14. Width of rectangle W = 5. L + 5 = 14. L = 9. Side of inner square = L - W = 9 - 5 = 4. Area of inner square = 4 * 4 = 16. Let's consider another possibility. Maybe 14 is L+W, and 5 is L-W. This led to inner side 5, area 25. Maybe 14 is L and 5 is W. This led to inner side 9, area 81. Outer side 19. Diagram label 14 (confusing). Maybe 14 is L+W and the outer square side is 14. And 5 is W. This led to inner side 4, area 16. (Not in options). Let's look again at the diagram. The 14 spans the entire width. The 5 spans the shorter side of one rectangle. If the side of the outer square is 14, and the width of the rectangle is 5, then L+W = 14 and W=5, so L=9. Side of inner square is L-W = 9-5 = 4. Area 16. Let's assume the option [B] 81 is correct. Then the area of the inner square is 81, so the side of the inner square is 9. Side of inner square = L - W = 9. From the diagram, the width W is 5. So L - 5 = 9, which means L = 14. Then the length of the rectangle is 14 and the width is 5. With L=14 and W=5, the side of the outer square is L + W = 14 + 5 = 19. However, the diagram labels the side of the outer square as 14. This is a clear contradiction. Let's assume the horizontal label 14 represents L, and the vertical label 5 represents W. So L=14 and W=5. Then the side of the inner square is L-W = 14-5 = 9. Area = 9*9 = 81. This matches option [B]. If L=14 and W=5, then the side of the outer square is L+W = 14+5 = 19. The diagram labels the side of the outer square as 14. It seems the diagram labels are inconsistent if we assume the standard construction. Let's assume the diagram labels mean that the length of the rectangle is 14 and the width is 5. This gives an inner square side of 14-5=9 and area 81. This matches option B. The label 14 above the outer square is likely intended to be L=14, and the label 5 on the side is intended to be W=5. Although the placement of the 14 label as the side of the outer square is visually misleading if L+W is the actual side length of the outer square. Given that 81 is an option, and assuming L=14 and W=5 leads to an area of 81 for the inner square, it's most likely that L=14 and W=5 is the intended interpretation, despite the confusing label on the outer square. Let's proceed with the assumption that the length of the rectangle is 14 分米 and the width is 5 分米. Length L = 14 分米. Width W = 5 分米. The side length of the central square formed by arranging the rectangles as shown is the difference between the length and the width of the rectangle. Side of central square = L - W = 14 - 5 = 9 分米. Area of central square = (Side)^2 = 9 分米 * 9 分米 = 81 平方分米. This result matches option [B]. Therefore, it is highly probable that the intended interpretation is that the dimensions of the rectangle are 14 分米 and 5 分米. The label 14 分米 above the diagram is likely meant to indicate the length of the rectangle, not the side of the outer square. Or, as discussed earlier, if L=14 and W=5, the side of the outer square is L+W=19. The label 14 above the outer square is inconsistent. However, if we assume the 14 and 5 are the dimensions L and W of the rectangle, then the side of the inner square is L-W, and the area is (L-W)^2. Let's verify the area of the outer square with L=14 and W=5. Side of outer square = L+W = 14+5 = 19. Area of outer square = 19 * 19 = 361. This is option [D]. The total area of the four rectangles is 4 * L * W = 4 * 14 * 5 = 280. This is option [C]. Area of outer square = Area of 4 rectangles + Area of inner square. 19 * 19 = 4 * (14 * 5) + (14 - 5)^2 361 = 4 * 70 + 9^2 361 = 280 + 81 361 = 361. This equation holds true if L=14 and W=5. The outer square has side 19, area 361. The four rectangles have dimensions 14x5, total area 280. The inner square has side 14-5=9, area 81. Given the options, it is most likely that the length of the rectangle is 14 分米 and the width is 5 分米. The label 14 分米 above the diagram should ideally indicate the length L=14, and the label 5 分米 should indicate the width W=5. Although the placement of the 14 label as the side of the outer square is confusing, the presence of 81 as an option strongly suggests that the inner square side is 9, derived from L-W = 9. With W=5, this gives L=14. Based on the options and the likely intended problem, I will assume L=14 and W=5 are the dimensions of the rectangle. Question Stem: (7) 芳芳用四个相同的长方形做拼图游戏,拼摆后图形的中间部分是个正方形。这个正方形的面积是 ( )。 Options: [A] 70平方分米 [B] 81平方分米 [C] 280平方分米 [D] 361平方分米 Chart/Diagram Description: Geometric diagram showing four identical rectangles arranged to form a larger square with a square hole in the center. The horizontal dimension across the top of the entire figure is labeled as 14 分米. The vertical dimension along the right side, corresponding to the shorter side of a rectangle, is labeled as 5 分米. The central area is a square. Interpretation (likely intended): Four identical rectangles with length L and width W are arranged. The central area is a square with side length L-W. The dimensions of the rectangle are L = 14 分米 and W = 5 分米. The side length of the central square is L - W = 14 - 5 = 9 分米. The area of the central square is (side length)^2 = 9 分米 * 9 分米 = 81 平方分米. Let's describe the chart elements based on this interpretation. The rectangle dimensions are 14 分米 by 5 分米. The outer square has side length L+W = 14+5 = 19 分米. The label 14 分米 above the outer square is misleading if it means the side length of the outer square. It is more likely indicating the length of the rectangle L=14. The label 5 分米 indicates the width W=5. Final output based on the most probable intended meaning given the options. Question Stem: (7) 芳芳用四个相同的长方形做拼图游戏,拼摆后图形的中间部分是个正方形。这个正方形的面积是 ( )。 Options: [A] 70平方分米 [B] 81平方分米 [C] 280平方分米 [D] 361平方分米 Other Relevant Text: None other than question stem and options. Mathematical Formulas/Chemical Equations: Area of a square = side * side Table Content: None. Chart/Diagram Description: * Type: Geometric diagram illustrating a puzzle made of four identical rectangles. * Main Elements: * Four identical rectangles arranged around a central square. * The outer boundary forms a larger square. * A horizontal dimension of 14 分米 is labeled above the entire width of the figure. * A vertical dimension of 5 分米 is labeled next to the shorter side of a vertical rectangle. * The central area is a square. * Labels and Annotations: * "14 分米" labeled horizontally above the top side. * "5 分米" labeled vertically to the right of the right side, next to a vertical bracket spanning the height of the shorter side of a rectangle. * Relative Position and Direction: Four rectangles are arranged around a central void. Two rectangles are oriented horizontally at the top and bottom, and two are oriented vertically on the left and right sides, creating a square gap in the middle. Interpretation from diagram and question: Assuming the dimensions of the identical rectangles are Length = 14 分米 and Width = 5 分米, based on the options. The side length of the central square is the difference between the length and the width of the rectangle (14 - 5 = 9 分米). Derived Calculation (not explicitly requested for extraction, but helps confirm interpretation): Length of rectangle (L) = 14 分米 Width of rectangle (W) = 5 分米 Side of central square = L - W = 14 - 5 = 9 分米 Area of central square = (9 分米)^2 = 81 平方分米.