We would find the area of each circular portrait by applying the formula for finding the area of a circle which is expressed as
Area = pi * radius^2
For the large portrait, diameter = 18
Radius = diameter/2 = 18/2 = 9 in
Area = pi * 9^2 = 81 pi
For the medium portrait, diameter = 6
Radius = diameter/2 = 6/2 = 3 in
Area = pi * 3^2 = 9 pi
The difference between the areas of the two sizes of portraits is
81pi - 9pi = 72pi
Since pi = 3.14, then
The difference between the areas of the two sizes of portraits is
72 * 3.14 = 226.08 inches^2
Rounding to the nearest whole number, it becomes
226 inches^2