Question

How to find the distance between a circle's center and a tangent line?

Answer 1

hello :
let an equation of the tangent line : ax+by = c
the center of the circle is : A(X0 ,Y0) 
the distance between a circle's center and a tangent line is : d 
d= |aX0 +bY0 - C| /(√(a²+b²)