How to calculate the area of the inscribed triangle?---**Extraction Content:** **Question Stem:** The question asks for the area of the inscribed triangle (indicated by "?面积"). **Other Relevant Text:** 长方形 = 80 (Rectangle = 80) The number 6 is indicated as a vertical distance from the top edge to a point on the right edge of the rectangle. The number 5 is indicated as a horizontal distance from the left edge to a point on the bottom edge of the rectangle. **Chart/Diagram Description:** * **Type:** Geometric figure (a rectangle with an inscribed triangle). * **Main Elements:** * **Rectangle:** A four-sided figure. * **Vertices:** Four vertices of the rectangle. Let's assume the top-left vertex is A, top-right is B, bottom-right is C, and bottom-left is D. * **Triangle:** A triangle is formed by connecting three points. One vertex is the top-left vertex of the rectangle (A). Another vertex (let's call it E) is on the right side (BC) of the rectangle. The third vertex (let's call it F) is on the bottom side (CD) of the rectangle. The triangle is AEF. * **Lines:** The sides of the rectangle and the sides of the triangle (AE, EF, FA). * **Labels and Annotations:** * "长方形 = 80" is written above the rectangle, indicating the area of the rectangle is 80. An arrow points from this text to the rectangle. * "？面积" is written inside the triangle, indicating the area of the triangle is the unknown quantity being asked for. * The number 6 is labeled on the right side of the rectangle, indicating the distance from the top edge (AB) to the point E on the right edge (BC). So, BE = 6. * The number 5 is labeled on the bottom side of the rectangle, indicating the distance from the left edge (AD) to the point F on the bottom edge (CD). So, DF = 5. The dimension 5 is measured from the bottom-left corner D. **Relative Position and Direction:** * The triangle AEF is inscribed within the rectangle ABCD. * Vertex A is the top-left corner. * Vertex E is on the right side BC, 6 units below the top edge AB (or from vertex B). * Vertex F is on the bottom side CD, 5 units to the right of the left edge AD (or from vertex D).