Triangle angles

Do the angles in a triangle always add up to the same thing? Would I ask it if they didn't? What do we know about the angles of a triangle if two of the sides are congruent (an isosceles triangle) or all three are congruent (an equilateral)? This tutorial is the place to find out.Common Core Standard: 8.G.A.5

Angles in a triangle sum to 180° proof

Find angles in triangles

Isosceles & equilateral triangles problems

Find angles in isosceles triangles

Triangle exterior angle example

Worked example: Triangle angles (intersecting lines)

Worked example: Triangle angles (diagram)

Finding angle measures using triangles

Triangle angle challenge problem

Triangle angle challenge problem 2