In a trapezoid, the two parallel sides are in the ratio 3 : 5. If the height of the trapezoid is 10 cm and its total area is 240 cm2, determine the lengths of the parallel sides.
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Correct answer: B
Explanation
The correct answer is Option 2 i.e. 18 cm and 30 cm.
Let the lengths of the parallel sides be 3x and 5x cm.
Area of trapezoid = (1/2) × (Sum of parallel sides) × Height
⇒ (1/2) × 8x × 10 = 240
⇒ 40x = 240
⇒ x = 240/40 = 6
Parallel sides: 3x = 3 × 6 = 18 cm and 5x = 5 × 6 = 30 cm