Find the radius of a circle whose center is (0,3) and a y-intercept of (0,7).

Answer 1

radius = 7-3 = 4

standard equation for a circle is

(x-h)^2 + (y-k)^2 = r^2 where (h,k) = center and r = radius, (h,k) = (0,3) r = 4

x^2 + (y-3)^2 = 16 IF you want multiply it out to get

x^2 + y^2 -6y + 9 = 16, then combine the constant terms to get

x^2 + y^2 -6y = 7

Answer 2

x² + (y - 3)² = r²

(0)² + (7 - 3)² = r²

4² = r²