Question

The area of a circular playground is 22176 m2. Find the cost of fencing this ground at the rate of Rs 50 per metreNCERT Class XMathematics - Exemplar ProblemsChapter _AREA RELATED TO CIRCLES

Answer 1

area of circular playground =pi.r^2
where r is the radius of playground .
now ,
22176 =22/7 x r^2
r^2= 22176 x 7/22 =7056
r=root {7056}=84m

now perimeter of playground=2.pi.r
=2 x 22/7 x 84 m
=528 m
now the cost of fencing =perimeter of playground x rate
=528 x 50 = 26400 Rs