第16题怎么写？用上题目中的全部条件。用初中生的语言,条理清晰。---Here is the extracted content from the image:
**Problem 12**
**Question Stem:**
[...] 如图, 在四边形 ABCD 中, AC ⊥ BD, 垂足为 O, AB [...] // CD. 要使四边形 ABCD 为菱形, 可添加的条件是 _________ (写出一个即可)
**Diagram Description:**
The diagram shows a quadrilateral ABCD. The diagonals AC and BD intersect at point O. The diagonals appear to be perpendicular at O (indicated by the text AC ⊥ BD). The side AB appears to be parallel to CD (indicated by the text AB // CD).
**Handwritten Answer:**
AB=CD
**Problem 13**
**Question Stem:**
[2024 福建泉州 期末, ★★★] 如图, 点 E 是正方形 ABCD 对角线 AC 上一点, 且 AB = AE, 连接 BE, 则 ∠DBE = ________ 度.
**Diagram Description:**
The diagram shows a square ABCD. The diagonal AC is drawn. Point E is located on the diagonal AC. The line segment BE is drawn.
**Handwritten Answer:**
22.5
**Problem 14**
**Question Stem:**
[2024 广西中考, ★★★] 如图, 两张宽度均为 3 cm 的纸条交叉叠放 在一起, 交叉形成的锐角为 60°, 则重合部分构成的四边形 ABCD 的周长为 _________ cm.
**Diagram Description:**
The diagram shows two overlapping strips. The strips have a uniform width of 3 cm. They intersect at an acute angle of 60°. The overlapping region forms a quadrilateral labeled ABCD. There is also another diagram showing a rhombus labeled AMBN with sides labeled '5'. A calculation '48' is handwritten near this diagram. The calculated answer '8√3' is handwritten next to the blank for the perimeter in the question stem.
**Handwritten Answer:**
8√3
**Problem 15**
**Question Stem:**
[2024 浙江台州 期末, ★★★] 如图, AB = 6 cm, 分别以 A, B 为圆心, 5 cm 长为半径画弧, 两弧相交于 M, N 两点. 连接 AM, BM, AN, BN, 则四边形 AMBN 的面积为 _________ cm².
**Diagram Description:**
The diagram shows a line segment AB. Two arcs are drawn, one centered at A with radius 5, and another centered at B with radius 5. The two arcs intersect at points M and N. The line segments AM, BM, AN, and BN are drawn, forming the quadrilateral AMBN. The length of AB is indicated as 6, and the radius of the arcs is indicated as 5.
**Handwritten Answer:**
24
**Problem 16**
**Question Stem:**
[2025 广东佛山 期中, ★★★] 如图, 正方形 ABCD 的边长是 8, E 是 AB 的中点, 连接 CE, 将 △BCE 沿 CE 折叠, 点 B 的对应点是 F, 连接 DF, 则 △CDF 的面积是 _________.
**Diagram Description:**
The diagram shows a square ABCD. The side length is indicated as 8. Point E is the midpoint of side AB. The line segment CE is drawn. Point F is the reflection of point B across the line segment CE, representing the result of folding triangle BCE along CE. The line segment DF is drawn.
**Handwritten Answer:**
(None visible)
**Other Text:**
初中试卷 数学 九年级 上册 北师大版 》》 第一章 素养提优测试卷 3◀