Answer:
Step-by-step explanation:
The equation of a circle of radius r centered at the origin is
x² + y² = r²
If the radius is 15, then the equation is x² + y² = 15² = 225
The equation of a circle with center (h,k) and radius r is
[tex](x-h)^2+(y-k)^2=r^2[/tex]
In your case, (h,k)=(0,0) and r=15, so the equation becomes
[tex]x^2+y^2=225[/tex]
