We worked through a longish example of finding the equation and length of the altitude of a triangle. A similar example in the form of a problem is in your textbook (pages 82-82, Example 1). It’s pretty neato.
Then we completed the following activity in small groups using chart paper and markers. The file below includes all of the triangles from class (each group had a different triangle). If you need extra practice, try some of the other triangles!