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Pizzas are sized by diameter. What percent increase in area results if Chantel's pizza increases from an 8-inch pizza to a 12-inch pizza?

 Jul 5, 2022
 #1
avatar+2275 
+1

Original pizza: \(4 ^2 \pi = 16 \pi\)

 

New pizza: \(6^2 \pi = 36 \pi\)

 

So, \(36 \div 16 = 2.25 = 225\text{%}\). But, recall that we are looking for the increase, so we subtract 100, to find that it is a \(\color{brown}\boxed{125 \text{%}} \) increase. 

 Jul 5, 2022
 #3
avatar+1105 
+7

my answer shows an easier way for the percentage step. but still. same answer! laugh

nerdiest  Jul 5, 2022
 #2
avatar+1105 
+9

An 8-inch pizza has a radius of 4 inches.

A 12-inch pizza has a radius of 6 inches.

 

Area of first pizza: \(\pi r^2\)\(= 16\pi\)

Area of second pizza: \(\pi r^2=36\pi\)

Calculation of percentage: \(\frac{36-16}{16} \times 100 = 125%\)%

 

Therefore, the area is increased by \(125\)%

 Jul 5, 2022

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