Question 143411
Starting with the general form of the equation of a circle (assuming the Frisby is circular) of radius r and center at (h, k):
{{{(x-h)^2+(y-k)^2 = r^2}}}
In the problem, the center is given as (-2, 1) and the radius is half the diameter so that's 12/2 = 6 inches.  Make the appropriate substitutions into the equation:
{{{(x-(-2))^2+(y-1)^2 = 6^2}}} Simplify.
{{{(x+2)^2+(y-1)^2 = 36}}}