Angles and Triangles

Front

What is an angle?

Back

An angle is formed by two rays (sides) that share a common endpoint (vertex). It is measured in degrees.

Front

What are complementary angles?

Back

Complementary angles are two angles whose measures add up to 90 degrees.

Front

What are supplementary angles?

Back

Supplementary angles are two angles whose measures add up to 180 degrees.

Front

What are vertical angles?

Back

Vertical angles are the angles opposite each other when two lines intersect. They are always congruent.

Front

What are alternate interior angles?

Back

Alternate interior angles are pairs of angles that are on opposite sides of a transversal and inside two parallel lines. They are congruent.

Front

What are corresponding angles?

Back

Corresponding angles are pairs of angles that are in the same position on two parallel lines in relation to a transversal. They are congruent.

Front

How do you classify triangles by angles?

Back

Triangles can be classified as acute (all angles < 90°), right (one angle = 90°), or obtuse (one angle > 90°).

Front

How do you classify triangles by side lengths?

Back

Triangles can be classified as equilateral (all sides equal), isosceles (two sides equal), or scalene (no sides equal).

Front

What is the Angle-Angle Similarity (AA ~) Theorem?

Back

The AA ~ Theorem states that if two angles of one triangle are congruent to two angles of another triangle, then the triangles are similar.

Front

What is a triangle's interior angle sum?

Back

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