Solution:Diameter of a circular garden = 21 m
Radius of a circular garden
To find the length of rope he needs to buy if he makes 2 laps of the fence, we need to find the perimeter of the circular garden.
Circumference of the circular garden,
The perimeter of the circular garden is 66 m, which means to fence the garden as soon as the gardener needs 66 m of rope.
To fence the garden twice = 2 X the perimeter of the circular garden
= 2 x 66 = 132 m
The gardener must purchase two rounds of rope for fencing = 132 m
Cost of one meter of rope = Rs. 4
Cost of 132 m of rope = 132 X 4 = Rs. 528.
Hence, the cost of the rope is Rs.528.
So the correct answer is option 1.