Diameter of the circular garden is 42 m. … [Given]
∴ Radius of the circular garden (r) = 42/2
= 21 m
Width of the road = 3.5 m …[Given]
Radius of the outer circle (R) = radius (r) + width of the road
= 21 + 3.5 = 24.5 m
Area of the road = area of outer circle – area of circular garden
= πR2 – πr2
= π(R2 – r2)
= (22/7) [(24.5)2 – (21)2]
= (22/7) (24.5 + 21) (24.5 – 21) ...[∵ a2 - b2 = (a + b)(a - b)]
= (22/7) x 45.5 x 3.5 = 22 x 45.5 x 0.5
= 500.50 sq. m
∴ The area of the road is 500.50 sq. m.
