What are Congruent figures? Lesson 3.1 Understand the concept of congruent figures and accurately identify the corresponding parts of figures.

Congruent figures: Same size, same shape All sides, angles, and points the same All sides, angles, and points the same Match up the same Match up the same

Ex.1: B Y A C X Z A C X Z If ABC = XYZ then  A   X,  B   Y,  C   Z andAB  XY, BC  YZ, CA  ZX * Notice letters match up in order

Definition:  all pairs of corresponding parts are . Definition:  all pairs of corresponding parts are . “implies” “If..., then...” “implies” “If..., then...” the statement is reversible the statement is reversible

In later chapters  polygons all pairs of corresponding parts are . In later chapters  polygons all pairs of corresponding parts are .

K I E I E T Ex. 2: ITK  ETK IK  EK IT  ET KT  KT (all use the reflexive property) Name Name  Name Sides Name  Sides KET is a reflection of KIT KET is a reflection of KIT IKT EKT IKT  EKT KET KIT KET  KIT Postulate: any segment or angle is congruent to itself (reflexive property) (reflexive property)

Try to justify each conclusion with one of the properties presented in Chapter 2 and in this section. A. Multiplication Property B. Subtraction Property C. Substitution D. Reflexive Property