Step-by-step explanation:
here's the answer to your question
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
Answer:
bottom side (a) = 3.36 ft
lateral side (b) = 4.68 ft
Step-by-step explanation:
We have to maximize the area of the window, subject to a constraint in the perimeter of the window.
If we defined a as the bottom side, and b as the lateral side, we have the area defined as:

The restriction is that the perimeter have to be 12 ft at most:

We can express b in function of a as:

Then, the area become:

To maximize the area, we derive and equal to zero:

Then, b is:
