Question

Each side of a square is increasing at a rate of 7 cm/s. at what rate is the area of the square increasing when the area of the square is 81 cm2?

Answer 1

Consider this option:
1. initial_area_sq=a²=81 (where a - the length of the side), it means, that a=9 cm.
2. according to the condition new_a=a+7=9+7=16 cm.
new area_sq=(new_a)²=256.
3. new_area_sq / initial_area_sq = 256/81≈3.160494.or 316.0494%.