126k views
5 votes
A cylindrical rod measures 8 inches long and the circumference of one of its bases is 8π inches. The rod is cut into two equally-sized pieces and then all surfaces are painted.

What is the area that is painted?

Use π≈3.14.

Enter your answer, rounded to the nearest tenth, in the box.

2 Answers

4 votes

Answer:

401.9

Explanation:

I got this question wrong on my quiz

User Myo
by
7.7k points
1 vote

Answer:

128π in.² ≈ 402.1 in.²

Explanation:

The rod can be cut into two equal sized pieces in different ways, so there are different answers to this question. I assume the question is asking when the rod's length is cut in half, so now there are two rods, each one being a cylinder with 4 inch height.

We need the area of the original rod and then add two more base areas.

C = 8π in.

r = 4 in.

total surface area = lateral area + 4 × area of base

SA = 8 in. × 8π in. + 4 × π × (4 in.)²

SA = 64π in.² + 64π in.²

SA = 128π in.² ≈ 402.1 in.²

User Suraj Menon
by
7.4k points