Triangle Classification & Triangle Sum

Front

What is a triangle?

Back

A triangle is a polygon with three edges and three vertices. It is one of the basic shapes in geometry.

Front

What are the types of triangles based on side lengths?

Back

1. Equilateral Triangle: All sides are equal. 2. Isosceles Triangle: Two sides are equal. 3. Scalene Triangle: All sides are different.

Front

What are the types of triangles based on angles?

Back

1. Acute Triangle: All angles are less than 90 degrees. 2. Right Triangle: One angle is exactly 90 degrees. 3. Obtuse Triangle: One angle is greater than 90 degrees.

Front

What is the Triangle Sum Theorem?

Back

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

Front

If one angle of a triangle is 90 degrees and another is 45 degrees, what is the measure of the third angle?

Back

The third angle is 45 degrees.

Front

What are vertical angles?

Back

Vertical angles are the angles opposite each other when two lines intersect. They are always congruent.

Front

If two angles of a triangle are 30 degrees and 60 degrees, what is the measure of the third angle?

Back

The third angle is 90 degrees.

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 a scalene triangle?

Back

A scalene triangle has all sides of different lengths and all angles of different measures.

Front

How do you classify a triangle with one angle greater than 90 degrees?

Back

It is classified as an obtuse triangle.