The length of a chain used as the boundary of a semicircular park is 108 m. Find the area of the park.
In this question the length of chain used as boundary of the semicircular park is the perimeter of the semicircular park. By using this we will first calculate the radius of the semicircular park and then area of semicircle consequently.
Length of chain = 108 m
Length of chain = Perimeter or circumference of semicircle
Therefore, Circumference or Perimeter of semicircle = 108 m
Also, Circumference or Perimeter of semicircle = πr
Where r = radius of semicircle
⇒ πr = 108
(put π = 22/7)
On rearranging,
⇒ r = 34.46 m
Therefore, radius of semicircle is 34.36 m
As, Area of semicircle 
Put value of ‘r’ in equation 1, we get
Area of semicircle
(put π = 22/7)
On rearranging,
= 1855.63 m2
The area of the semicircular park is 1855.63 m2.