Question

Surface Area of a Cylinder

3 cm
3 cm
7 cm

1. What is the surface Area of a Cylinder in terms of π
A. 70π cm ²
B. 50π cm²
C. 40π cm²
D. 60π cm²

2. What is the surface area of the cylinder, in terms of π, if the height of the cylinder is increased by 1 cm?
A. 72π cm²
B. 62π cm²
C. 66π cm²
D. 68π cm²

Answer 1

1) D

2) C

Explanation:

1. The formula for the surface area of a cylinder is 2πr² + 2πrh, where r is the radius of the base and h is the height of the cylinder.

Given that the radius of the cylinder is 3 cm and the height is 7 cm, we can substitute these values into the formula to get:

SA = 2π(3)² + 2π(3)(7) = 2π(9) + 2π(21) = 18π + 42π = 60π cm²

Therefore, the answer is (D) 60π cm².

2. If the height of the cylinder is increased by 1 cm, the new height would be 8 cm.

We can use the same formula to find the new surface area:

SA = 2π(3)² + 2π(3)(8) = 2π(9) + 2π(24) = 18π + 48π = 66π cm²

Therefore, the answer is (C) 66π cm².