Question

The center of the fountain is located at (-4,8). The radius of the fountain is 25 feet. What equation could represent the edge of the fountain ?
A. (x+4)^2+(y-8)^2=5
B. (x+4)^2+(y-8)^2=25
C. (x+4)^2+(y-8)^2=625
D. (x-4)^2+(y+8)^2=625

Answer 1

well the general form of a circle with centre at (h, k) and radius r

is

\[(x - h)^2 + (y - k)^2 = r^2\]

substitute the information you have been given and then simplify

Answer 2

I don't even know that you have to know the center of the circle as long as you have that the radius is 25. Using the circumference formula, we get C = pi(50) for around that circle with a radius of 25. I can't see any other way to do this, unless I am missing something somewhere!