A park is in the form of a rectangle 120 m by 90 m. At the centre of the park, there is a circular lawn as shown in the figure. The area of the park excluding the lawn is 2950 m2. Find the radius of the circular lawn. [Given, π = 3.14]
Given:
Length of the rectangular park = 120 m
Breadth of the rectangular park = 90 m
Area of the park excluding the circular lawn = 2950m2
Area of the rectangular park = length × breadth
= 120 × 90
= 10800m2
Area of circular lawn = Area of rectangular park – Area of park excluding the lawn
= 10800 – 2950
= 7850m2
∵ Area of circle = πr2
∴ 7850 = 3.14 × r2
r2 = 
= 2500
r = √2500 = 50 m
Hence, the radius of the circular lawn is 50m.
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