Question

A park is in the form of a rectangle 120 m × 100 m. At the centre of the park there is a circular lawn. The area of park excluding lawn is 8700 m^2. Find the radius of the circular lawn.(use π = \(\frac{22}7\))

Answer 1

Total area of rectangular park = 120 ×100 = 12000 m² 

Area of park excluding circular lawn = 8700 m² 

So,

Area of circular lawn = 1200 – 8700 = 3300 m² 

= πr² = 3300

r² = \(\frac{3300\times7}{22}\) = 1050 m

r = 32.40 m

Answer 2

Total area of the park = 120 x 100 = 12000

Area excluding the lawn = 12000 - πr^2 = 8700 (given)

So, πr^2 = 3300

\(\frac{22r^2}{7}\) = 3300

r^2 = 1050

So, r = root 1050

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