Question

If the length of a rectangle is increased by 5%, then its area will increase by: 
1. 10%
2. 5%
3. 7.5%
4. 25%

Answer 1

Correct Answer - Option 2 : 5%

Formula used:

Area of rectangle = length × breadth

Calculation:

Let the length and breadth of a rectangle be l and b respectively

Initial area of rectangle = l × b

New length = l + 5% of l = 1.05 l

New area of rectangle = 1.05 l × b

Increase in area = (1.05 l × b) – (l × b) = 0.05 × l × b

Percentage increase = (0.05 × l × b)/(l × b) × 100 = 5%

∴ The area of rectangle will increase by 5%