Classifying Triangles, Interior & Exterior Angle Sum Theorem

Front

What is an exterior angle in a triangle?

Back

An exterior angle is formed by one side of a triangle and the extension of an adjacent side. It is equal to the sum of the two remote interior angles.

Front

What is the Triangle Sum Theorem?

Back

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

Front

What type of triangle has all sides of different lengths?

Back

A scalene triangle.

Front

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

Back

Each angle in an equilateral triangle measures 60°.

Front

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

Back

It is a right triangle.

Front

What is the relationship between interior and exterior angles?

Back

An exterior angle is equal to the sum of the two opposite interior angles.

Front

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

Back

Subtract the sum of the known angles from 180°.

Front

What is an acute triangle?

Back

An acute triangle is a triangle where all three angles are less than 90°.

Front

What is an isosceles triangle?

Back

An isosceles triangle has at least two sides that are equal in length and the angles opposite those sides are equal.

Front

What is the measure of the angles in a triangle with angles of 50° and 60°?

Back

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