Question

A park is in the shape of a rectangle. Its length and breadth are 240 m and 100 m, respectively. At the centre of the park. there is a circular lawn. The area of the park, excluding the lawn is 3904 m2. What is the perimeter (in m) of the lawn? (use π = 3.14 )

• A. 502.4
• B. 516.2
• C. 508.6
• D. 512.8

Answer 1

Answer:

A. 502.4

Solution:

GIVEN:-

 Length and Breadth of the rectangular park = 240 m and 100 m, Area of the park, excluding the lawn = 3904 m²

FORMULA USED:-

Area of Rectangle = Length × Breadth 

Area of Circle = πR²

The perimeter of Circle  = 2πR

Area of the rectangular park - Area of the circular lawn

CALCULATION:-

⇒ 240 × 100 - πR² = 3904 

⇒ 3.14 × R² = 24000 - 3904 = 20096

⇒ R² = 20096 ÷ 3.14 = 6400 

⇒ R = 80 m

The radius of the circular lawn = 80 m

⇒ Perimeter of circular lawn = 2πR

⇒  2 × 3.14 × 80 = 502.4 m

∴ The perimeter of the circular lawn = 502.4 m