The side of a square is increased from 20cm to 21cm. Calculate the percentage increase in its area
A
2.5%
B
9.3%
C
10.0%
D
10.25%
Verified Correct Answer: D.
Step-by-Step Mathematical Solution
old area = 20\(^2\) = 400
new area = 21\(^2\) = 441
% increase in area \(=\frac{41}{400}\times \frac{100}{1}\)
=10.25%
Source: Myschool Past Questions Archive (Record #26378)