Question

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

Answer 1

the answer is ( x - 1)^2 + ( y - 4)^2 = 25

This is because the formula for the equation of a circle is (x - h)^2 + (y - k)^2 = r^2 and when you plug in the numbers you get the answer above in standard form

Answer 2

notice the picture below




you have the center, the h,k, all you really need is the radius "r"