#### Answer

The diameter of the circle is 63 centimeters.

#### Work Step by Step

Let x represent the diameter of the circle that we need to find.
Now, let’s set up a proportion with the ratio given and a ratio which compares the circumference of the circle to the diameter of the circle.
$\frac{22}{7}$ = $\frac{198}{x}$
To solve this equation, we equate the cross products.
22 $\times$ x = 7 $\times$ 198
22x = 1386
Divide both sides by 22.
x = 63
The diameter of the circle is 63 centimeters.