Triangle Sum Theory

Front

What is the Triangle Sum Theory?

Back

The Triangle Sum Theory states that the sum of the interior angles of a triangle is always 180 degrees.

Front

What is an acute angle?

Back

An acute angle is an angle that measures less than 90 degrees.

Front

What is a right angle?

Back

A right angle is an angle that measures exactly 90 degrees.

Front

What is an obtuse angle?

Back

An obtuse angle is an angle that measures more than 90 degrees but less than 180 degrees.

Front

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

Back

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

Front

If two angles in a triangle are 25° and 66°, what is the measure of the third angle?

Back

The third angle measures 89° (180 - 25 - 66 = 89).

Front

What is the measure of each angle in an equilateral triangle?

Back

In an equilateral triangle, each angle measures 60 degrees.

Front

What is the relationship between the angles in a right triangle?

Back

In a right triangle, one angle is 90 degrees, and the sum of the other two angles is 90 degrees.

Front

What is the formula for the sum of angles in a triangle?

Back

The formula for the sum of angles in a triangle is A + B + C = 180°, where A, B, and C are the measures of the angles.

Front

What is the definition of complementary angles?

Back

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