This school year my younger son is working through Art of Problem Solving’s Precalculus book. This week we started chapter 4 -> Applications to Geometry. The first section is on right triangle trig.

As we started working through the example problems, I was struck by technique my son was using to work through the problems. Once he finished, we went back through one of the problems on camera to share the technique.

Here’s the problem and how he got started:

Next he dove into the solution. His technique is to first draw a right triangle with a hypotenuse of 1 and then scale up:

Finally – here’s how he solved the equation he found in the last video (with some not so great calculator help from me . . . )