Angles of a Triangle

Front

What is the sum of the angles in a triangle?

Back

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

Front

If one angle of a triangle is 90 degrees, what type of triangle is it?

Back

It is a right triangle.

Front

What do you call an angle that is less than 90 degrees?

Back

An acute angle.

Front

What do you call an angle that is greater than 90 degrees but less than 180 degrees?

Back

An obtuse angle.

Front

If two angles in a triangle are equal, what type of triangle is it?

Back

It is an isosceles triangle.

Front

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

Back

All angles in an equilateral triangle are equal and measure 60 degrees.

Front

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

Back

Subtract the sum of the known angles from 180 degrees.

Front

If angle A is 56 degrees and angle B is 36 degrees, what is angle C?

Back

Angle C is 88 degrees (180 - 56 - 36).

Front

What is the exterior angle theorem?

Back

The exterior angle of a triangle is equal to the sum of the two opposite interior angles.

Front

If angle A is 70 degrees and angle B is 50 degrees, what is the measure of the exterior angle at vertex C?

Back

The exterior angle at vertex C is 120 degrees (70 + 50).