Question

The height and curved surface area of a right circular cylinder are 7 cm and 70 π . Its total surface area is:

• A. 140 π
• B. 150 π
• C. 180 π
• D. 120 π

Answer 1

Answer:

D. 120 π

Curved Surface Area = 2πrh Total surface area = 2πr(r + h) Curved surface area = 70π 2πr × 7 = 70π r = 5 cm Total surface area = 2πr(r + h) = 2 × π × 5 × (5 + 7) = 2 × π × 5 × 12 = 120π