Angles in Triangles

Front

What is the Exterior Angle Theorem?

Back

The Exterior Angle Theorem states that the measure of an exterior angle of a triangle is equal to the sum of the measures of the two non-adjacent interior angles.

Front

How do you find the measure of an angle in a triangle if you know the measures of the other two angles?

Back

To find the measure of an unknown angle in a triangle, subtract the sum of the known angles from 180 degrees.

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

What is the relationship between the angles in an isosceles triangle?

Back

In an isosceles triangle, the angles opposite the equal sides are also equal.

Front

How do you solve for an unknown angle in a triangle using algebra?

Back

Set up an equation based on the known angles and the fact that their sum equals 180 degrees, then solve for the unknown.

Front

What is a right triangle?

Back

A right triangle is a triangle that has one angle measuring 90 degrees.

Front

What is the Pythagorean theorem?

Back

The Pythagorean theorem states that in a right triangle, the square of the length of the hypotenuse is equal to the sum of the squares of the lengths of the other two sides.

Front

What is the definition of complementary angles?

Back

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

Front

What is the definition of supplementary angles?

Back

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

Front

How can you determine if a triangle is acute, right, or obtuse?

Back

A triangle is acute if all angles are less than 90 degrees, right if one angle is exactly 90 degrees, and obtuse if one angle is greater than 90 degrees.