Question

The radius of a circular ground is $56m$. Inside it, runs a road of width $7m$ all along its boundary. Find the area of this road.

Answer 1

The radius of circular ground$=56m$

Width of road (inside) $=7m$

The radius of inner circle$=56-7=49m$

Hence, area of road$=$ Area of outer circle $-$ Area of inner circle

$=\pi (56{)}^2-\pi (49{)}^2$ [$\because$ Area of circle $=\pi r^2$]

$=\pi (3136-2401)$

$=\frac{22}{7}\times 735$

$=2310m^2$.​