[tex]SA=2 \pi r^2+2 \pi rh[/tex]
This is the formula for the surface area where r is the radius and h is the height. Finding the surface area will determine how much wrapping paper Jill needs (in inches squared).
The base measures 4 inches across. This means that the diameter is 4 inches. The radius is half the diameter (always). Thus, the radius is 2 inches. This means that r=2
The height is 10 inches. This means that h=10
The questions says to use 3.14 for π.
[tex]SA=2(3.14)(2^2)+2(3.14)(2)(10)[/tex]
Use a calculator for this. Doing this by hand will take a painful amount of time.
[tex]SA=150.72[/tex]
This was what I got from a calculator. I did not round at all.
The surface area is 150.72 inches squared. Thus, Jill will need 150.72 inches squared of wrapping paper. I hope this is what you needed to help you understand! :)
