If the height of a regular right pyramid with a square base is increased by 20% and the side length of its base is decreased by 10%, what is the percentage change in its volume?
Show answer & explanation
Correct answer: A
Explanation
Height increased by 20%, base length decreased by 10%
according to formula
Volume = (1/3)a²h
New volume = (0.9a)² × (1.2h) = 0.972
Change = (0.972 − 1) × 100 = −2.8%