A path of width 3.5m runs around a semi-circular grassy plot whose perimeter is 72m. find the area of the path.
Given,
Perimeter of semi-circle = 72m
Width of path around it = 3.5m
Perimeter of semi-circle = πr+2r
= r +2r = 72
= 22r+14r = 72×7
r = = 14cm
Radius including the width of path(R) = r+3.5 = 14+3.5 = 17.5m
So, area of path =
= 173.25m2