ANSWER :
The center-radius form of the circle equation is in the format (x – h)2 + (y – k)2 = r2, with the center being at the point (h, k) and the radius being "r". This form of the equation is helpful, since you can easily find the center and the radius.
All you do is use the a+b=c formula lets plug it in
15+b=35
15+20=35
35=35
The answer is 20
T-shirt costs $4
Sweater costs $4(4)
Sweater costs 4 x 4
4 x 4 = 16
Sweater costs $16
hope this helps
