Question

A circular garden has a water body which is in the shape of a circle with diameter 14 m.The remaining part of the garden is covered with grass and this portion is 7 m wide. Find the area of the lawn in $m^2$

___

• A. $412c{m}^2$
• B. $432c{m}^2$
• C. $512c{m}^2$
• D. $532c{m}^2$

Answer 1

The correct option is B $432c{m}^2$

Radius of the inner circle = 7 m

Radius of the outer circle = 14 m

Area of lawn = Area of the whole garden - Area of the water body

$=\pi {14}^2-\pi 7^2$

$=\pi ({14}^2-7^2)$
[using the identity $a^2-b^2=(a+b)(a-b)]$

$=\frac{22}{7}\times 21\times 7=462m^2$