How much more pizza is in a 12-in. diameter pizza than an 8-in. diameter pizza?

Question

How much more pizza is in a 12-in. diameter pizza than an 8-in. diameter pizza?

Round your answer to the nearest hundredth.

Be sure to show all work and label your answer

 

Im not sure what to do at all. Help please!

Answer 1

With round pizza we need to

find the area of each pizza in

square inches, then determine

the difference.  

The area of a circle is given by:

A = πr²

 

12 inch diameter, radius = 6

a = π(6²) = 36π in²

 

8 inch diameter, radius = 4

a = π(4²) = 16π in²

 

Difference:  36π - 16π = 20π in²

 

using 3.14 for pi, the difference is

20(3.14) = 62.8 in²

Answer 2

I think you are looking for the difference in area between the two pizzas. The area formula is pi*r^2.

 

Additional area = pi * 6² - pi * 4²

Original area = pi * 4²

 

Since the question is how much bigger the answer should probably be in the form of a fraction or a percentage.

 

The fraction would be Additional area / Original area to turn it into a percentage just multiply by 100