Question

NEED THIS ASAP Write the equation of a circle with a center at (1, 4) where a point on the circle is (4, 8).

(x - 4)2 + (y - 1)2 = 25
(x - 1)2 + (y - 4)2 = 25
(x - 1)2 + (y - 4)2 = 5
(x + 1)2 + (y + 4)2 = 25

Answer 1

(x-1)^2 + (y-4)^2 = 5^2

Explanation:

Using the standard equation of a circle with center at (h, k) and radius r:

(x-h)^2 + (y-k)^2 = r^2, we substitute 1 for h, 4 for k, 4 for x and 8 for y:

(4-1)^2 + (8-4)^2 = r^2, or

9 + 16 = 25 = r^2

Thus, the radius is 5

and the equation is (x-1)^2 + (y-4)^2 = 5^2. This matches the 2nd answer choice.