Isosceles and Equilateral Triangles
aligned to Savvas Envision Geometry
Learning Objective
I can apply properties of isosceles and equilateral triangles to determine unknown angle measures and side lengths.
Lesson Flow
Watch Video
Equilateral and isosceles example problems | Congruence | Geometry | Khan Academy
Khan Academy
Guided Notes
Key concepts students will learn:
- •
In an isosceles triangle, the two base angles are congruent, meaning they have the same measure.
- •
If all three sides of a triangle are congruent, then all three angles are congruent and each angle measures 60 degrees, making it an equilateral triangle.
- •
If two sides of a triangle are congruent, the angles opposite those sides are congruent, and the sum of all angles in the triangle equals 180 degrees.
Practice
12 questions • Multiple choice & Short answer
Exit Ticket
“Triangle PQR is isosceles with PQ = PR. If angle P measures 28°, find the measure of angle Q.”
Teacher Guide
Get the complete package:
- Answer keys for all questions
- Differentiation strategies
- Extension activities
- Printable student handouts
