Question

Please answer:
Joanna bakes a cake in the shape of a
cylinder. The cake is 10 inches in
diameter and 4.5 inches tall. She
wants to put frosting on the entire
cake that is not resting on the tray.
How many square inches of frosting
will she need?

Answer 1

The cake has a cylindrical format, and the outside of the cake will be frosted, which means that the total surface area has to be found, and doing this, we find that she will need 298.5 square inches of frosting.

Surface area of a cylinder:  

The surface area of a cylinder of radius r and height h is given by:

$S = 2\pi r^2 + 2\pi rh$

The cake is 10 inches in  diameter and 4.5 inches tall.

Radius is half the diameter, so $r = \frac{10}{2} = 5$.

The height is $h = 4.5$.

How many square inches of frosting  will she need?

This is the surface area, so:

$S = 2\pi(5)^2 + 2\pi(5)(4.5) = 50\pi + 45\pi = 95\pi = 298.5$

She will need 298.5 square inches of frosting.

A similar problem can be found at https://brainly.com/question/24332238

Answer 2

Answer:

Step-by-step explanation:

First of all, we need the formula of a cylinder which is: 2$\pi$rh + 2$\pi$$r^{2}$

BUT also remember we are solving for one base since we do not count the bottom of the tray. That formula would look like this: 2$\pi$rh + $\pi$$r^{2}$ since we are using 1 base instead of 2.

Now input the missing values into the formula and solve:

2$\pi$rh + $\pi$$r^{2}$

2$\pi$(5)(4.5) + $\pi$$(5^{2})$

45$\pi$ + 25$\pi$ = 70$\pi$

Our Answer is 70$\pi$, or 219.91 $in^{2}$