Using the proportion of parallel lines to determine the missing length of a triangle

The video tutorial covers the concept of triangle proportions and the proportionality theorem, particularly in the context of parallel lines. It demonstrates how to solve a proportion problem using given side lengths and concludes with a calculation to find the unknown variable. The lesson emphasizes understanding the theorem and applying it correctly to solve mathematical problems.

What calculation is performed to find the value of X in the equation presented?

What is the final result for X after solving the equation?