Question

Which of the following is an equation of the circle with its center at (0,0) that passes through (3,4) in the standard (x,y) coordinate plane?

Answer 1

General equation of the circle is (x-h)^2 -(y-k)^2 = r^2

Given, center of the circle is at (0,0) i.e.  h=0 and k=0

Also r^2 = 3^2 + 4^2 (using distance formula between two points, (0,0) and (3,4) )

So the equation of the circle is

x^2 + y^2 = 25