# Thread: length of a tangent to circle

1. ## length of a tangent to circle

How do you find the length of the tangent to a circle from a point outside circle (6,4) .
The circle has radius 5 and centre point(-1,-2).

2. Originally Posted by heatly
How do you find the length of the tangent to a circle from a point outside circle (6,4) .
The circle has radius 5 and centre point(-1,-2).
If O is the center, P is the point and PT is the tangent, then OT is the radius.
And OTP is a right angle triangle. Find OP. Use the property of right angled triangle to find PT.