Triangles: Classifying Triangles & Theorems

Front

What are the three types of triangles based on side lengths?

Back

Equilateral, Isosceles, Scalene.

Front

What is an equilateral triangle?

Back

A triangle with all three sides of equal length and all angles measuring 60°.

Front

What is a scalene triangle?

Back

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

Front

What is an isosceles triangle?

Back

A triangle with at least two sides of equal length and the angles opposite those sides are equal.

Front

What is the Triangle Sum Theorem?

Back

The sum of the interior angles of a triangle is always 180°.

Front

If one angle of a triangle measures 36°, what is the sum of the other two angles?

Back

144° (since 180° - 36° = 144°).

Front

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

Back

Each angle measures 60°.

Front

How can you determine if a triangle is scalene?

Back

If all three sides are of different lengths.

Front

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

Back

The angles opposite the equal sides are equal.

Front

What is the formula to find the third angle in a triangle if two angles are known?

Back

Third angle = 180° - (first angle + second angle).