Finding more angles  Angles and intersecting lines  Geometry  Khan Academy  Summary and Q&A
TL;DR
In this video, the instructor solves triangle angle problems by using the properties of triangles and parallel lines.
Questions & Answers
Q: How do you determine the measure of the largest angle in a triangle?
In this video, the measure of the largest angle is determined by multiplying the measure of the second largest angle by 4.
Q: What is the equation used to solve for the angles in a triangle?
The equation used is that the sum of all angles in a triangle is equal to 180 degrees.
Q: How do you identify corresponding angles in parallel lines?
Corresponding angles in parallel lines are formed when a transversal intersects the parallel lines. They have equal measures.
Q: How do you determine the measure of a supplementary angle?
Supplementary angles are angles that add up to 180 degrees. In this video, the instructor uses the fact that two adjacent angles formed by parallel lines are supplementary.
Summary & Key Takeaways

The largest angle in a triangle is 4 times the measure of the second largest angle, and the smallest angle is 10 degrees.

The measures of the angles in a triangle add up to 180 degrees.

Using these properties and equations, the instructor solves the triangle angle problem and determines the measures of all three angles.