Animation of Angle Sum of Triangle
Animation that the sum of the angles of a triangle is a straight angle; α+β+γ=180°
Click and drag the the vertices of the triangle to change the angles!
How did we choose the segment for the reflection of point B? (Hint: Check the box for midpoints.)
How did we choose the segments for the reflections of point A and point C?
Which pairs of triangles are congruent (equal)?
How does this animation show that the sum of the angles of any triangle is 180°?