Interior Angles of Triangles

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°.

Front

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

Back

It is a right triangle.

Front

What is an acute angle?

Back

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

Front

What is an obtuse angle?

Back

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

Front

How do you find the missing angle in a triangle?

Back

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

Front

If two angles of a triangle are 65° and 75°, what is the measure of the third angle?

Back

The third angle measures 40° (180° - 65° - 75° = 40°).

Front

What is the definition of a triangle?

Back

A triangle is a polygon with three edges and three vertices.

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°.

Front

What is a scalene triangle?

Back

A scalene triangle is a triangle with all sides of different lengths and all angles of different measures.

Front

What is an isosceles triangle?

Back

An isosceles triangle is a triangle with at least two sides of equal length and two angles of equal measure.