Answer:
ANGLE SUM PROPERTY OF A TRIANGLE
Explanation:
PROPERTY 1 : Angle sum property of triangle states that the sum of interior angles of a triangle is 180°.
PROOF : Draw a triangle , then mark each angle as A , B , and C . then take a compass and mark three ark in three sides of a triangle and cut the angles of B and C , then join the two angle B and C with angle A . Then you will find there a COMPLETE ANGLE .