# Types of triangles review

CCSS Math: 4.G.A.2
Review ways to classify triangles based on their sides lengths and angles.  Practice classifying triangles.

## Classifying triangles by their angles

### Acute triangles

An $\blueD{\text{acute}}$ triangle has $\blueD{\text{3 angles that}}$ $\blueD{\text{each measure less than } 90^\circ}$. Below are examples of $\blueD{\text{acute triangles}}$.

### Right triangles

A $\purpleD{\text{right}}$ triangle has $\purpleD{\text{1 angle that measures } 90^\circ}$ and $2$ acute angles. Below are examples of $\purpleD{\text{right triangles}}$.

### Obtuse triangles

An $\greenD{\text{obtuse}}$ triangle has $\greenD{\text{one angle that measures}}$ $\greenD{\text{more than } 90^\circ}$ and $2$ acute angles. Below are examples of $\greenD{\text{obtuse triangles}}$.
Problem 1A
Classify $\triangle{PQR}$ by its angles.

Want to try more problems like this? Check out this exercise

## Classifying triangles by their side lengths

### Equilateral triangles

An $\blueD{\text{equilateral}}$ triangle has $\blueD{\text{three equal sides}}$. Below are examples of $\blueD{\text{equilateral}}$ triangles.

### Isosceles triangles

An $\purpleD{\text{isosceles}}$ triangle has $\purpleD{\underline{\text{at least}}}$ $\purpleD{\text{two equal sides}}$. Below are examples of $\purpleD{\text{isosceles}}$ triangles.

### Scalene triangles

A $\greenD{\text{scalene}}$ triangle has $\greenD{\text{no equal sides}}$. Below are examples of $\greenD{\text{scalene}}$ triangles.
Problem 2A
Classify $\triangle{PQR}$ by its sides.