Explanation:
Let radius of circle is r=18 units
Perimeter of full circle is given by 2πr
Thus, perimeter of three quarters circle is given by,
( ¾ × 2πr) + (2 × r)
The perimeter of this "circle" would be:
( ¾ × 2 × π × 18) + (2 × 18) = 27π + 36 ≈ 120.78 m