. A circular park is surrounded by a rod 21 m wide. If the radius of t

1.	. A circular park is surrounded by a rod 21 m wide. If the radius of the park is 105 m,find the area of the road.NCERT EXEMPLAR
Answer» Let radius of the circular park = r = 105 m Width of the road surrounded by the Park = w = 21 m Radius of the outer circle = R = r + w R = 105 + 21 = 126 m Area of the road = area of the outer circle - area of the inner circle A = pi × R ^2 - pi × r ^2 A = pi ( R ^2 - r ^2 ) A = pi × ( R + r ) ( R - r ) A = pi × ( R + r ) × w Substitute the values A = 22/ 7 × ( 126 + 105 ) × 21 A = 22 × 231 × 3 A = 15246 square meters. Therefore, Area of the road = 15246sq meters

. A circular park is surrounded by a rod 21 m wide. If the radius of the park is 105 m,find the area of the road.NCERT EXEMPLAR

Answer»

Let radius of the circular park = r = 105 m

Width of the road surrounded by the

Park = w = 21 m

Radius of the outer circle = R = r + w

R = 105 + 21 = 126 m

Area of the road = area of the outer

circle - area of the inner circle

A = pi × R ^2 - pi × r ^2

A = pi ( R ^2 - r ^2 )

A = pi × ( R + r ) ( R - r )

A = pi × ( R + r ) × w

Substitute the values

A = 22/ 7 × ( 126 + 105 ) × 21

A = 22 × 231 × 3

A = 15246 square meters.

Therefore,

Area of the road = 15246sq meters