Angles, Triangles, and Transversal lines

• One of the special properties of a triangle is that the sum of all three interior angles is always equal to 180 degrees
• Exterior angles - angles on the outside of the triangle
• Transversal line - a line that cuts through two parallel lines

  
• Corresponding angles - angles that are in the same position in relation to the transversal and therefore congruent

  
• Alternate exterior angles - angles on opposite sides of a transversal and outside the parallel line

  
• Alternate interior angles - angles that are on opposite sides of a transversal and inside the parallel line