I taught Segments in Triangles as a mini-unit this year. I spent one day on midesgments and two days on altitudes, angle bisectors, perpendicular bisectors, and medians. Then, I spent one day on the Triangle Inequality Theorem. Then, review and test.
I used this flip book for all of the segments in triangles. I used a powerpoint (which is unusual for me) to go through the vocabulary and examples. It worked well in class and it was nice to not have to write so much while the students were writing.
Day 1 - Midsegments
We completed the midsegments tab in the flip book. Then, I gave each student a paper triangle and had them fold the midsegment of the triangle. They glued it onto the next page. They added to this page as we went through the unit.
After that, I had students complete this practice sheet with their partners. We went over it as a class and I had them write out the Midsegment Theorem again at the bottom of the page. Muscle memory.
Day 2 - Altitudes and Perpendicular Bisectors
I combined the perpendicular lines into one lesson. First, we completed the tabs in the flip book. Then, I gave each student a paper triangle. I had them draw an altitude on the triangle using a notecard as a straight edge. Some students had triangles with altitudes outside the triangle. I had a student demonstrate trying to draw the altitude inside when it was supposed to be outside on the document camera.
Day 3 - Angle Bisectors and Medians
This day was the same as the others. We completed the tabs in the flip book and I had students fold the angle bisectors of a triangle I gave them. They added it to the paper folding page.
Day 4 - Triangle Inequality Theorem
I used a discovery activity at the beginning of this lesson. I gave each student a small handful of Q-Tips and had them make a triangle. I made a list on the board of side lengths. Then, I had students make a three sided figure that wasn’t a triangle and I made a list of side lengths. We did this a could of times. Then, I had students make a conjecture based on the lists. My students are very shaky with anything they have to do on their own, so this was a low pressure way to try help develop this skill. Then, we completed the next two pages as a class and with partners. (download page 1) (download page 2)
That was the entire unit. I liked teaching it as a mini-unit.