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Author:
Seth Marx

To understand what isosceles triangles are: how to spot them, what their congruencies are, and how to find their angles.

This packet shows a video explaining isosceles triangles. It goes through typical isosceles problems, and is awesome in general.

Tutorial

Isosceles Triangle: a triangle with at least 2 equal sides and 2 equal angles

Base angles: the congruent angles of an isosceles triangle

Vertex angle: the third angle of an isosceles triangle formed by the legs, not congruent with the other two (unless its an equilateral triangle)

Legs: the two congruent sides of an isosceles triangle; opposite the base angles

Base: the third side of an isosceles triangle; forms base angles with the legs

This video explains isosceles triangles and how to find their angles.