Two parallel sides of a trapezium are 29 cm and 21 cm. Non-parallel sides are equal and each is of length 8.5 cm. What is the area of the trapezium?
- A. 187.5 square cm ✓
- B. 227.5 square cm
- C. 375 square cm
- D. 455 square cm
Correct Answer: A. 187.5 square cm
Explanation
Dropping perpendiculars from the shorter parallel side to the longer one creates two identical right triangles with bases \frac{29-21}{2} = 4\text{ cm}. The height h = \sqrt{8.5^2 - 4^2} = \sqrt{72.25 - 16} = 7.5\text{ cm}. The area is \frac{1}{2}(29+21) \times 7.5 = 25 \times 7.5 = 187.5\text{ cm}^2.
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