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# Triangles! The Types of Triangles and How to Classify Them

## Triangle Basics

A triangle has several key components.

A triangle always has three sides, the sides are connected and create the shape.

A triangle is a polygon ( a multi sided figure).

A triangle has three angles. These angles always add to make 180° (degrees).

## Classified by the Triangles Sides

When classifying the triangle by it's sides there are three choices. In order to figure out if a triangle is classified by one of these methods it is important to note that the sides can be measured with a ruler or the figure may have has marks to show that two sides are equal.

**Equilateral** - meaning that all three sides have the exact same measure.

**Isosceles** - two side are equal with a third side being a different measure

**Scalene** - all three sides have different measures

## Classifying Triangles by their Angles.

Another method of classifying triangles is by their angles. In order to determine the classification you would need to measure the angles with a protractor in order to determine the angles measure. Arcs within a figure also mark whether two angles of congruent.

Acute - all of the angles in the triangle are less than 90°.

Right- There is exactly one right (90°) angle in the triangle. There could never be more than one because it could not form a triangle with two right angles and only three sides.

Obtuse - The triangle has one angles that is greater than 90°

## Triangles!

Important to note that a triangles can be classified in one way or in both ways. I can say that a triangle is both equilateral and acute because it describes two different things about the triangle.