Question

Q. 4. A gardener wants to fence a circular garden of diameter 21 m. 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 π = 22/7 )


Well explanation needed. ​

Answer 1

Diameter of the circular garden=21m

∴ Radius of the circular garden=221​m

Now, circumference of circular garden=2πr=2×722​×221​

=22×3=66m

The gardener makes 2 rounds of fence so the total length of the rope of fencing =2×2πr=2×66=132m

Since the cost of 1 meter rope=Rs. 4

Therefore, cost of 132 meter rope=4× 132=Rs. 528.

Answer 2

Step-by-step explanation:

Diameter of the circular garden (r) = 21 m

Radius of the circular garden (r) = 21/2 m

Therefore,

Circumference of the circular garden

• 2πr
• 2 × 22/7 × 21/2 m = 66m

Length of the rope needed to make 1 round of fence= 66 m

Length of the rope needed to make 2 round of fence= 66×2 = 132 m

Cost of rope per meter= Rs. 4

So, Cost of the rope = Rs. 132 × 4 = Rs. 528.

hope it helps you.