Question

a Gardner wants to fence a circular garden of diameter 21m.Find the length of the rope he needs to purchase of he makes 2 rounds of fence. Also find the cost of the rope ,if it costs RS.4 per metre.(Take π=22/7)

Answer 1

radius=21/2 me,

circumference of the circular garden=22/7 × 21/2 × 21/2,

=11×3×21/2,


then

total length of the rope which is required for 2 rounds = 2 × 11×3×21/2,

=11×3×21 me,

therefore

total cost=4 × 11×3×21,

= 2772 rs

Answer 2

Answer:

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