Single correct option
An isosceles trapezium has parallel sides of length 10 cm and 22 cm, and each non-parallel side is 10 cm. What is its area?
- A. 120 cm²
- B. 128 cm²
- C. 144 cm²
- D. 112 cm²
Show answer and solution
Answer: (B) 128 cm²
Drop perpendiculars from the ends of the shorter side. The longer base extends (22 − 10)/2 = 6 cm beyond each foot.
Height = √(10² − 6²) = 8 cm.
Area = ½ × (10 + 22) × 8 = 128 cm².
Tip: In an isosceles trapezium the overhang on each side is half the difference of the parallel sides.
Height = √(10² − 6²) = 8 cm.
Area = ½ × (10 + 22) × 8 = 128 cm².
Tip: In an isosceles trapezium the overhang on each side is half the difference of the parallel sides.
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