### LESSON 4-8 PROBLEM SOLVING ISOSCELES AND EQUILATERAL TRIANGLES Well, the base angles are going to be congruent. So we have a bunch of congruent segments here. Well, this angle right over here is supplementary to that degrees. And because it’s isosceles, the two base angles are going to be congruent. We think you have liked this presentation. And we are done. Let’s do this one right over here. This is one leg. Did I do that right? The angle created by the intersection of the legs is. And so if we call this x, then this is x as well.

Now, this angle is one of the base angles for triangle BCD. You can kind of imagine it was turned upside down.

I have to figure out B. Well, this angle right over here is supplementary to that degrees. The two congruent legs form. So you call that an x. And in particular, we see that triangle ABD, all of its sides are equal. Well, that’s part of angle ABE, but we have to figure out this other part right over here. The vertex angle is the angle formed by the legs. And we need to figure xnd this orange angle right over here and this blue angle right over here. And we’ll do it the exact same way we just did that second part of that problem. BC has the same length as CD. Definitions – Review Define an isosceles triangle. So we could say 31 degrees plus 31 degrees plus the measure of angle ABC is equal to degrees.

MICHAEL POLLAN OMNIVORES DILEMMA THESIS

## 4-8 Isosceles and Equilateral Triangles Lesson Presentation

So you get 2x plus– let me just write it out. Don’t want to skip steps here. Those are the two legs of an isosceles triangle. Apply properties of isosceles and equilateral triangles.