Question

The radius of a circular park is $50m$.A circular concrete footpath of width $5m$ is construction around the park. Find the cost of construction at the rate of $Rs50per{m}^2$ ?

Answer 1

Area of the circle$=\pi r^2,r=5m$

$A=\frac{22}{7}\ast 5\ast 5=78.57m^2$

$\therefore$ the area of the path=$\pi (R+r{)}^2$

$=\frac{22}{7}(50+5{)}^2$

$=\frac{22}{7}\ast {55}^2$

$=9507.14m^2$

Cost of construction$=50\ast 9507.14=Rs.475357$