Two tangents drawn from the same point outside of the circle
are the same length and form two congruent right triangles
How to Use the Circle Theorem where Tangents from the Same Point Are the Same Length
The tangent OA is 10 cm in length. What is the length of the tangent OB?
Tangents drawn from the same point outside of the circle have the same length.
OB = OA = 10 cm
The tangent OB has length 10 cm.
The slider below shows a real example of the circle theorem where tangents from the same point are equal.
is a line that touches the circle at one point.
Tangents from the Same Point Form Right Congruent Triangles
triangles are the same shape. The corresponding sides and angles are the same.
The tangents from the same point form congruent right triangles
with the radii to the tangents and the line halfway between the tangents.
The two right triangles have the same angles and side lengths as each other.