3.1 Sum of Interior Angles of a Triangle

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 two angles of a triangle are 70° and 60°, what is the measure of the third angle?

Back

The third angle is 50° (180° - 70° - 60° = 50°).

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 find the measure of a missing angle in a triangle?

Back

To find the missing angle, subtract the sum of the known angles from 180 degrees.

Front

If one angle of a triangle is 90° and another is 30°, what is the measure of the third angle?

Back

The third angle is 60° (180° - 90° - 30° = 60°).

Front

What is the relationship between the angles in a triangle?

Back

The angles in a triangle are related such that their sum is always 180 degrees.

Front

What is the formula to calculate the sum of interior angles of a polygon?

Back

The formula is (n-2) × 180°, where n is the number of sides in the polygon.

Front

What type of triangle has all angles less than 90°?

Back

A triangle with all angles less than 90° is called an acute triangle.