Answer:
approximately 3.24 times greater
Explanation:
The formula for the area of a circle of radius r is A = πr². Because we are given the diameter here (not the radius), we substitute d/2 for r in the above formula, obtaining:
A = π(d/2)²
Case 1: A = π [18 in / 2]² = π(9 in)² = 81π in²
Case 2: A = π[10 in/2]² = π[5 in]² = 25π in²
Dividing 81π in² by 25π in² gives us the desired result:
The area of the larger pizza is 81/25 times the area of the smaller one, or approximately 3.24 times greater.