# The sum of the angles in a triangle?

- Author:
- GreenMaths

Move the slider GreenAngle to change the sizes of the angles.
For different shapes of triangles what do you notice about the three angles?
There are more things to try below.

- Position the slider on 90°. What kind of triangle is this?
- Now move the slider to 40°. What name do we give to this shape of triangle?
- Move the slider to 130°. Does this shape have the same name?
- Can you move the slider or the points so that two angles are the same size? What name do we give to this shape of triangle?
- What do you notice as the green angle is increased to a maximum?
- What do you notice as the green angle is decreased to almost zero?
- What happens when you nmove the blue point at the top of the triangle?