By what factor larger is a 12 inch pizza than a 10 inch pizza?
A) 1.2
B) 1.1
C) 1.4
D) 1.6

Question

Quizplus · Accepted Answer

The area of a circle is calculated using the formula A = πr^2. 
So, the area of a 10 inch pizza is A = π(5)^2 = 25π. 
The area of a 12 inch pizza is A = π(6)^2 = 36π. 
The ratio of the two areas is 36π/25π = 1.44. 
Therefore, the 12 inch pizza is 1.44 times or 44% larger than the 10 inch pizza. 
Rounded to the nearest tenth, this is approximately 1.4 times larger. So, the answer is C.

By What Factor Larger Is a 12 Inch Pizza Than