A circular pond is surrounded by a path 2 m wide. If the total area (pond + path) is 1386 m2 and the pond area is 1134.57 m2, what is the radius of the pond?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 19 m.
Let the radius of the pond = r m
Radius of pond + path = (r + 2) m
π(r + 2)2 = 1386
⇒ (22/7)(r + 2)2 = 1386
⇒ (r + 2)2 = 441
⇒ r + 2 = 21
⇒ r = 21 - 2 = 19 m