Angle Relationships and Triangles

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 equal.

Front

What are adjacent angles?

Back

Adjacent angles are two angles that share a common side and a common vertex but do not overlap.

Front

How do you find the measure of an unknown angle in a triangle?

Back

The sum of the angles in a triangle is always 180 degrees. Subtract the sum of the known angles from 180 to find the unknown angle.

Front

If one angle measures 65 degrees, what is the measure of its complementary angle?

Back

The complementary angle measures 25 degrees (90 - 65 = 25).

Front

If two angles are supplementary and one measures 130 degrees, what is the measure of the other angle?

Back

The other angle measures 50 degrees (180 - 130 = 50).

Front

What is the sum of the interior angles of a triangle?

Back

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

Front

If angle 1 is 44 degrees, what is the measure of angle 3 if they are vertical angles?

Back

Angle 3 also measures 44 degrees because vertical angles are equal.

Front

What is the measure of an angle if it is 10 degrees less than its supplementary angle?

Back

Let the angle be x. Then, x + (x + 10) = 180. Solving gives x = 85 degrees.