The surface area of a cylinder can be found using the formula A = 2πr² + 2πrh, where r is the radius and h is the height.
For the first cylinder, A = 2π(1²) + 2π(1)(3) = 2π + 6π = 8π.
For the second cylinder, A = 2π(3²) + 2π(3)(9) = 18π + 54π = 72π.
The ratio of their surface areas can be found by dividing the larger surface area by the smaller surface area:
72π / 8π = 9
Therefore, the ratio of their surface areas is 9.
Answer: C. 1/9.
Question 9 of 20
Use the image to answer the question.
The cylinders shown below are similar.
Two cylinders are shown side by side. The first cylinder has a height of 3 inches and a radius of 1 inch. The second cylinder has a height of 9 inches and a radius of 3 inches.
What is the ratio of their surface areas?
A.
1
27
B.
3
27
C.
1
9
D.
1
3
1 answer