Triangle Proofs

Front

What is the definition of congruent triangles?

Back

Triangles that have the same size and shape, meaning their corresponding sides and angles are equal.

Front

What does SAS stand for in triangle congruence?

Back

Side-Angle-Side; a criterion for triangle congruence where two sides and the included angle of one triangle are equal to two sides and the included angle of another triangle.

Front

What is the definition of vertical angles?

Back

Angles that are opposite each other when two lines intersect; they are always congruent.

Front

What is the definition of alternate interior angles?

Back

Angles that are on opposite sides of a transversal and inside the two lines; they are congruent when the lines are parallel.

Front

What is the Angle-Angle (AA) criterion for triangle similarity?

Back

If two angles of one triangle are equal to two angles of another triangle, the triangles are similar.

Front

What is the definition of a bisector in geometry?

Back

A line or segment that divides an angle or a segment into two equal parts.

Front

What is the definition of corresponding angles?

Back

Angles that are in the same position on two parallel lines cut by a transversal; they are congruent.

Front

What is the definition of a triangle's exterior angle?

Back

An angle formed outside a triangle when one side is extended; it is equal to the sum of the two opposite interior angles.

Front

What is the definition of the Triangle Sum Theorem?

Back

The sum of the interior angles of a triangle is always 180 degrees.

Front

What is the definition of isosceles triangle?

Back

A triangle with at least two sides of equal length.