Answer:
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.