Expression for tangent to circle from outside point

[manjunath MK]

Hi there,

Could someone help with expression for a 2 tangents to a circle.

Reference (calculations inside circle not requried)

https://www.geogebra.org/m/uMbEdSWy

[manjunath MK]

Another example

https://www.geogebra.org/m/Hf4DCGPG

[Mylenium]

The page you linked has all the math already. It's just a simple triangle which can be solved with the law of cosines or even simpler using the standard formula for equilateral triangles. The circle itself doesn't really matter beyond defining the points of the triangle as being on a radius relative to a center.

Mylenium

[manjunath MK]

LoL! I constructed one in geogebra in below link

https://www.geogebra.org/m/b6hrv4nq

But while implementing in after effects, when 2 circles intersect, how do you find the intersection point coordinates(x,y) to draw a perpendicular bisect and a midpoint to act as center for new circle which intersects again on original circle on point of tangency.

[Mylenium]

Simple math again. The bisection of two circles is the intersection of their cosine/ sine functions with the intersection point being the same value in both function sets in a coordinate system.

Mylenium