Width - Pizza Crust

[Challa]

A pizza has a 3" radius for the pizza portion. The pizza has a total area of 25 pi sq. in. due to inclusion of the crust. Determine width of the crust.

Area of a circle - pi * r^2.

3.1416 * 3 * 3 = 28.8744 sq. in.

How do I proceed from this point ?

[Baltuilhe]

Good night!

Area (total):
[tex]A_t=25\pi[/tex]

Calculating the radius:
[tex]A=\pi R^2=25\pi\\
R^2=25\\
R=\sqrt{25}\\
R=5''[/tex]

So, if pizza has 3'' and due to inclusion of the crust, 5'', crost width is 2''.