How to use the triangle bisector theorem to solve your missing length

The video tutorial explains the properties of triangles, focusing on angle bisectors and the proportionality of sides. It demonstrates how to set up and solve ratios, particularly in the context of finding unknown side lengths. The instructor uses algebraic methods, including cross multiplication, to solve for a variable, ensuring students understand each step of the process. The tutorial concludes with a reminder to verify calculations.

Explain the process of cross multiplication as applied in the problem.

What was the final calculated value of B, and how was it derived?