Question 54

A park is in the shape of a rectangle. Its length and breadth 240 m and 100 m, respectively. At the centre of the park, there is a circular lawn. The area of the park, excluding the lawn is 3904 $$m^2$$. What is the perimeter (in m) of the lawn? (use $$\pi = 3.14$$)

Solution

Area of whole park = $$240\times100=24000$$ $$m^2$$

Area of the lawn = $$24000-3904=20096$$ $$m^2$$

Let radius of lawn = $$r$$ m

=> $$\pi r^2=20096$$

=> $$3.14\times(r)^2=20096$$

=> $$r^2=\frac{20096}{3.14}=6400$$

=> $$r=\sqrt{6400}=80$$

$$\therefore$$ Perimeter of lawn = $$2\pi r$$

= $$2\times3.14\times80=502.4$$ m

=> Ans - (A)

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