# Thread: Find a Point on the Cricle

1. ## Find a Point on the Cricle

Hi.

I have the slope of a tangent line.

I have a circle and know its radious and origin. However I need to calculate the point this tangent line comes in contact with the circle, so I can completely solve for the equation of the tangent line.

2. Originally Posted by CaliMan982
Hi.

I have the slope of a tangent line.

I have a circle and know its radious and origin. However I need to calculate the point this tangent line comes in contact with the circle, so I can completely solve for the equation of the tangent line.
The line perpendicular to the tangent line passing through the center of the circle intersect the circle line at the tangent point.

1. Calculate the equation of a line perpendicular to the tangent and passing through the center of the circle: point-slope-formula

2. Calculate the intersection between the circle line and the normal to the tangent: substitution method.

3. There are allways 2 tangent points.