Triangle Proofs

Front

What is the definition of an isosceles triangle?

Back

A triangle with at least two congruent sides and two congruent angles (base angles).

Tags

CCSS.4.G.A.2

Front

What does it mean for two angles to be vertical angles?

Back

Vertical angles are the angles opposite each other when two lines intersect, and they are always congruent.

Tags

CCSS.7.G.B.5

Front

What is the congruence statement for two triangles that have two pairs of congruent sides and the included angle congruent?

Back

The triangles are congruent by the Side-Angle-Side (SAS) postulate.

Tags

CCSS.HSG.SRT.B.5

Front

What is the definition of congruent segments?

Back

Congruent segments are line segments that have the same length.

Tags

CCSS.8.G.A.2

Front

What is the Angle-Angle (AA) similarity postulate?

Back

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

Tags

CCSS.HSG.SRT.B.5

Front

What is the definition of corresponding angles?

Back

Corresponding angles are angles that are in the same position on two parallel lines cut by a transversal.

Tags

CCSS.8.G.A.5

Front

What is the definition of alternate interior angles?

Back

Alternate interior angles are pairs of angles that are on opposite sides of the transversal and inside the two lines.

Tags

CCSS.8.G.A.5

Front

What is the definition of a scalene triangle?

Back

A triangle with all sides of different lengths and all angles of different measures.

Tags

CCSS.4.G.A.2

Front

What is the definition of a triangle's base angles?

Back

The angles opposite the base of an isosceles triangle, which are congruent.

Tags

CCSS.HSG.CO.C.11

Front

What is the definition of the Triangle Sum Theorem?

Back

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

Tags

CCSS.8.G.A.5