Presentation on theme: "CONGRUENT ANGLES & BISECTOR OF AN ANGLE. Definition of Congruent Angles Two angles are said to be congruent if and only if they have the same measure."— Presentation transcript:
Definition of Congruent Angles Two angles are said to be congruent if and only if they have the same measure. There is a phrase if & only ifwhich means that the definition is two way. 1) If the angles are congruent, then they are equal. 2) If the angles are equal, then they are congruent.
ILLUSTRATION: In the figure, If A = 55 ° and B = 55 °, then A B If A B, then m A =m B A 55° 55° B
Definition of Bisector of an Angle The bisector of an angle is a ray that divides an angle into two congruent angles. ILLUSTRATION: In the figure, if ray BF A F Is an angle bisector, then It divides ABC into two B C equal parts. And ABF CBF. NOTE: LIKE MARKINGS INDICATES EQUAL PARTS
Angle Addition Postulate If F is in the interior of ABC, then m ABF +m FBC= m ABC. Then ray BF is called angle bisector of the angle. A F B C NOTE: LIKE MARKINGS INDICATES EQUAL PARTS