Question

20) 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 ₹ 4 per meter. (Take π = 22/7)
1 point
66 m and 264 rupees
132 m and 528 rupees
42 m and 168 rupees
100 m and 400 rupees​

Answer 1

42 meters 168 rupees

Answer 2

Answer:

$\fbox \pink{diameter} = 21m \\ \\ \fbox \purple{radius} = \frac{21}{2}m \\ \\ \fbox \red{circumference} = 2\pi \: r \\ \\ 2 \times \frac{22}{7} \times \frac{21}{2} = \frac{22}{7} \times 21 \\ \\ 22 \times 3 = 66m \\ \\ \fbox \green{length \: of \: rope \: required} = 2 \times 66 = 132m \\ \\ \fbox \blue{cost} = 1m \: rope = 4 \\ \\ 132m \: rope = 4 \times 132 = 528$