# Classifying Triangles by Angles (version 2)

There are 4 classifications of triangles by angles. You are probably familiar with them, but glance at the following applets if you need a reminder.

## Acute Triangles

## Acute Triangles

As you drag point B, notice the angles of the triangle. How would you define an acute triangle?

## Obtuse Triangles: For this triangle, you can drag the slider to enlarge the triangle or vertex A to change the shape.

## Obtuse Triangles

What do you notice about the angles in the triangle? Using those observations, how would you define an obtuse triangle?

## Right Triangles

For this triangle, you can drag the slider to enlarge the triangle or the blue dot to change the shape.

## Right Triangles

What stayed the same no matter how you changed the triangle? How would you define a right triangle?

Drag the blue point on the triangle until you have two angles that both measure 45 degrees. This triangle has a special name: isosceles right triangle. What could you say about the lengths of two sides of an isosceles right triangle?

## Equiangular Triangle

Use the slider to adjust the size of the triangle.

## Equiangular Triangle

## Equiangular Triangle

How would you define an equiangular triangle?

What is another name for this type of triangle (think back to your previous exploration).