\[t = \sqrt{d^2-r^2}\]
Variables
ttangent length (m)
ddistance from external point to center (m)
rradius (m)
Description
What is this formula?
This formula calculates the length of a tangent segment drawn from an external point to a circle.
When to use it
Use this formula when the distance from an external point to the center of a circle and the circle radius are known.
Example
If the external point is 13 m from the center and the radius is 5 m:
t = √(13² - 5²) = 12 m
Applications
- Geometry and trigonometry
- Engineering design
- Surveying and construction
- CAD and technical drawing
- Mechanical and structural analysis