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

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

Back

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

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

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

Back

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

Front

What is the definition of 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 the exterior angle theorem?

Back

The exterior angle theorem states that the measure of an exterior angle is equal to the sum of the measures of the two non-adjacent interior angles.

Front

How can you determine if a triangle is valid based on its angles?

Back

A triangle is valid if the sum of its interior angles equals 180°.

Front

What is the formula for calculating the angles in a triangle when two angles are known?

Back

If two angles are known, the third angle can be found using the formula: Third Angle = 180° - (Angle 1 + Angle 2).