Sum of the Angles in a Triangle
- Author:
- Mr. Coffie, GreenMaths
- Topic:
- Angles
How can drawing a line through the top vertex of the triangle that is parallel to the base
help to show that the sum of the three angles in a triangle is 180°?
Directions:
1. Move the vertices of ∆ABC around by dragging them.
2. Notice that the angles change when you move the vertices.
3. Click to place a check in the checkbox.
4. Pull the red slider to watch the animation.
5. Drag the vertices of ∆ABC again. What do you observe?
What do you know about the sum of the 3 angles at the top of the triangle?
What must the sum of the 3 angles of a triangle equal?
Click Reset to start over.