Isosceles and Equilateral Triangles

Front

vertex angle

Back

angle formed by the two congruent sides

Front

leg

Back

one of the two congruent sides of an isosceles triangle

Front

base angles

Back

the two angles formed by the base and one of the congruent sides of an isosceles triangle

Front

Equilateral Triangles

Back

triangles with three congruent sides and three congruent angles of 60 degrees each

Front

The legs of an isosceles triangle are congruent

Back

both legs of an isosceles triangle have the same length

Front

The base angles of an isosceles triangle are congruent

Back

the angles formed by the base and each of the congruent sides are equal in measure

Front

If two sides of a triangle are congruent, then the angles opposite those sides are congruent

Back

a triangle with two congruent sides has two congruent angles opposite those sides

Front

The altitude drawn from the vertex angle to the base of the isosceles triangle is always the perpendicular bisector of the base

Back

the line drawn from the vertex angle to the base of an isosceles triangle is perpendicular to the base and divides it into two equal parts

Front

altitude

Back

a line segment drawn from a vertex of a triangle perpendicular to the opposite side.