Circle Theorem: Tangents from the Same Point Are the Same Length
Circle Theorem: Tangents from the Same Point Are the Same Length
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 that Tangents from the Same Point Are the Same Length
Question
The tangent OA is 10 cm in length. What is the length of the tangent OB?
Step-by-Step:
1
Tangents drawn from the same point outside of the circle have the same length.
OB = OA = 10 cm
Answer:
The tangent OB has length 10 cm.
See Also
What is a right triangle? What is a radius? What is a circle? What are the circle theorems?Interactive Test
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Here's a second test on the circle theorem on tangents from the same point
Here's a second test on the circle theorem on tangents from the same point
Note
Useful Definitions
A tangent is a line that touches the circle at one point.
Tangents from the Same Point Form Right Congruent Triangles
Congruent 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.