Question

A gardener wants to fence a circular garden of diameter 21m.find the length of the wire he needs to purchase and cost of it at the rate of Rs.4 per meter.

Answer 1

Given, Diameter = 21m, cost of the rope = Rs 4 per meter, length of the rope required to fence the garden two round=?, Cost of the rope = ?

The length of rope required = 2 × circumference.
Circumference = 2 π r = π D
= (22/7) × 21 = 66 m

Therefore, length of rope required = circumference × 2 = 66 m × 2 = 132 m

Cost of rope = Rate × length
= 4 × 132 = Rs. 528

Answer 2

length of wire = circumference = πD
= 21π metres or appr 66 m

cost = 4(21π) = 84π
= 263.89 or appr Rs 264