A cylindrical tank of height 10 m and radius 5 m has a small circular cut of 0.5 m radius on its top surface. What would be the total surface area of the tank?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e 470.31 m2 .
TSA = 2πRh + πR2 + πR2 = 2πRh + 2πR2
TSA (full) = 2πR(h + R) = 2π × 5(10 + 5) = 2π × 5 × 15 = 150π
Hole area = πr2 = π(0.5)2 = π × 0.25
New TSA = 150π − 0.25π = (150 − 0.25)π = 149.75π
⇒ 149.75 × π ≈ 149.75 × 3.1416 ≈ 470.31 m2