how much bigger is the area of a pizza with a diameter of 18 inches than the area of a pizza with a diameter of 10 inches

approximately 3.24 times greater

Step-by-step 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.