Question

the inner circumference of a circular park is 220 m . the park is 7.5 m wide every where. calculate the cost of putting up a fence along the outer circle at the rate of 4 per meter. also find the area of park. find the cost of levelling the park if the cost of levelling per meter square is 8.

Answer 1

given,
circumference=
$2\pi r$
220 m = 2 × 22/7× r
r = 220×7/2×22
= 35m
the width of the park= 7.5
the sum of the outer and inner radius
= ( 35 + 7.5) m
= 42.5m

the cost of fencing 1m fence = rs 4
the cost of fencing the inner and outer circle
= rs ( 42.5×4)
= rs 170.0
= rs 170

the area of the park
$\pi \: r {}^{2}$
= 22/7× 35×35
= 3850 m2

the cost of levelling of 1 m2= rs 8
the cost of levelling the park
= rs ( 3,850× 8)
= rs 30,800