A cylinder tube with caps on both ends is used to safely carry a rolled up poster. The tube is 42 inches tall with a radius of 1

Question

3 years ago

13

A cylinder tube with caps on both ends is used to safely carry a rolled up poster. The tube is 42 inches tall with a radius of 1

.5 inches. If one mini can of spray paint covers 150 square inches, how many mini spray cans of red paint would be needed to cover the entire tube?
A. 3
B. 2
C. 1
D. 4

If anyone know this kind of math, I really need help with it. Im not very good in math and I have testing coming soon. Thanks!

Mathematics

1 answer:

Romashka-Z-Leto [24] · Answer 1 · 2022-03-18T01:54:49+03:00

Romashka-Z-Leto [24]3 years ago

6 0

Find surface area
SA=2pir^2+2hpir

h=42
r=1.5

SA=2pi1.5^2+2(42)pi1.5
SA=4.5pi+126pi
SA=130.5pi square inches

area/areacoverdperspray≤numberofsprays
130.5pi/150
2.73
so buy 3 cans because you can't get 0.73 cans

A