A triangle has an area of 240 cm². If the base is increased by 20% and the corresponding height decreased by 10%, find the percentage change in the area.
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Correct answer: D
Explanation
Initial Area = 240 cm²
Increase in Base = 20%
Decrease in Height = 10%
New Base = 1.2b
New Height = 0.9h
Area of Triangle = (1/2) × Base × Height
New Area = (1/2) × 1.2b × 0.9h
= 1.08 × (1/2 bh)
= 1.08 × 240 = 259.2
Change = 259.2 − 240 = 19.2
Percentage Change = (19.2 / 240) × 100 = 8%