A solid cylinder has a radius of 9 cm and a height of 25 cm. What is the ratio of its total surface area to its curved surface area ?
Answer & explanation
Correct answer: option 4
We know that,
Total surface area of cylinder = 2 × π × r × (r + h)
Curved surface area of cylinder = 2 × π × r × h
Where, r = radius
h = height
According to the question,
= TSA = 2 × π × 9 × (9 + 25)
= TSA = 2 × π × 9 × (9 + 25)
= TSA = 18 × π × 34 = 612π
Now CSA
= CSA = 2 × π × 9 × 25
= CSA = 225 × 2 × π = 450π
Now TSA : CSA
= TSA : CSA = 612π : 450π
= TSA : CSA = 612 : 450
= TSA : CSA = 34 : 25