Explore: Angle Bisector Theorem
Students:
This GeoGebra task applet accompanies the Angle Bisector Theorem (Part 1) Lesson Activity
Angle Bisector Theorem
As per the Angle Bisector theorem,
the angle bisector of a triangle bisects the opposite side in such a
way that the ratio of the two line-segments is proportional to the ratio
of the other two sides. Thus the relative lengths of the opposite side
(divided by angle bisector) are equated to the lengths of the other two sides of the triangle. This theorem is applicable to all types of triangles.
What is Angle Bisector Theorem?
An angle bisector is a straight line
drawn from the vertex of a triangle to its opposite side in such a way,
that it divides the angle into two equal or congruent angles. Now let us
see, what is the angle bisector theorem.
Here is an example:
Suppose we are told a line segment AD divides side a into CD and DB, of lengths 10 cm and 30 cm. We are also told side CA is 30 cm and side BA is 90 cm. See if the ratios are proportional to each other:
CD/DB = CA/BA
10/30 = 30/90
References
https://byjus.com/maths/angle-bisector-theorem/