Circle in Standard Form

Question

What is the equation of a circle in standard form when the Center is (1,-4) and the Point on Circle is (-9,-2)

Answer 1

(x-h)² + (y-k)² = r²

• (h,k) = location of center = (1,-4)
• r = radius

 

(x-h)² + (y-k)² = r²

(x-1)² + (y-(-4))² = r²

(x-1)² + (y+4)² = r²

 

To find r², plug in the given point on the circle (-9,-2):

 

(x-1)² + (y+4)² = r²

(-9-1)² + (-2+4)² = r²

 

Can you finish it?