Q.4 A gardener wants to fence a circular garden of diameter 21m. Find the length of the rope he needs to purchase, if he makes 2 rounds of fence. Also find the cost of the rope, if it costs Rs. 4 per meter. (Take \(\pi = \frac{22}{7} \))

Given: Diameter of the circular garden = 21 m
\(\therefore Radius = \frac{21}{2} \) m
\(\therefore \)Circumference =\( 2\pi r = 2×\frac{22}{7}×\frac{21}{2} = 66 m \)
Length of rope needed for 2 rounds = 2 × 66 m = 132 m
Cost of the rope = Rs. 4 × 132 = Rs. 528