
Doug C. answered 06/20/22
Math Tutor with Reputation to make difficult concepts understandable
To find center radius form you need to determine the radius of the circle, which is the distance from the given center (4,9) to the given point on the circle (9,0). Use the distance formula.
R = √(9-4)2+(9-0)2 = √25+81 = √106
So center radius form is (x-4)2+(y-9)2 = 106
To get to standard form square each binomial, combine similar terms (subtracting 106 from both sides):
x2-8x+16 + y2-18y+81=106
You should be able to take it from there.