Question

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 4$ per meter. ( Take π as 22/7 )

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Answer 1

a). total length of rope=132 m

b). total cost of the rope=$528

Explanation:

Step 1

To get the total length of rope needed to cover the circular garden twice, we express this as;

P=πD

where;

P=perimeter

π=pi

D=diameter

In our case;

π=22/7

D=21 m

replacing;

P=(22/7)×21=66 m

2×P=2×66=132 m

total length of rope=132 m

Step 2

The expression to calculate the total cost can be written as;

total cost=cost per meter length×total length of rope

where;

cost per meter=$4

total length of rope=132 m

replacing;

total cost=4×132=$528

total cost of the rope=$528