Sum of interior angles in a triangle

Author:
PGelisa2
Topic:
Geometry
Sum of interior angles in a triangle: Procedure: 1) Find the midpoints of AC and BC 2) Connect the midpoints to form the midsegment 3) Form the perpendicular folding lines to base AB 4) Mirror the vertices A B and C to A' B' and C' around the folding lines by using the gliders 5) Show the angles A' B' and C'