If the radius of a sphere is increased by 50%, find the percent increase in surface area.
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 125%
Surface area of a sphere ∝ $r^2$
Given:
Radius is increased by 50%
$\text{New radius} = 1.5r$
New surface area:
$(1.5r)^2 = 2.25r^2$
Increase in surface area:
$2.25r^2 - r^2 = 1.25r^2$
$\text{Percentage increase} = 1.25 \times 100 = 125\%$