Question

High Order Thinking Skills (HOTS)
10. If the height of a triangle is decreased by 40%
and its base is increased by 40%, what will be
the percentage change in its area?​

Answer 1

Answer:

let x be the base and y be the height of the triangle.

area of triangle : 1/2xy = 0.5xy

height is decreased by 40% = 60y/100

base is increased by 40% = 140x/100

new area : 1/2 * 140x/100 * 60y/100 = 42 xy/100 = 0.42xy

change in area : 0.5 xy - 0.42xy/0.5xy * 100

= 0.08xy /0.5xy * 100 = 16%

thus the percentage change in its area would be 16%