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Chapter 4 Congruent Triangles. Sec. 4 – 1 Congruent Figures. Objective: 1) To recognize figures & their corresponding parts. Congruent Polygons. Are the same size and the same shape. Fit exactly on top of each other Have corresponding parts: Matching sides and s.
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Chapter 4Congruent Triangles Sec. 4 – 1 Congruent Figures Objective: 1) To recognize figures & their corresponding parts
Congruent Polygons • Are the same size and the same shape. • Fit exactly on top of each other • Have corresponding parts: • Matching sides and s
You can make 3 kinds of moves so that one congruent figure can fit exactly on top of top of another turn slide
You can make 3 kinds of moves so that one congruent figure can fit exactly on top of top of another flip flip These are called translations and are covered in chapter 9
You can make 3 kinds of moves so that one congruent figure can fit exactly on top of top of another slide
flip flip
ΔQXT ΔPHD Means you can list the corresponding parts without a diagram QX PH
Naming Polygons • Order Matters!! When naming, always list cooresponding points in order C B U T AB ED B D A WU RS U S W A W R S E D ABCDE WUTSR
Example: ΔWYS ΔMKV • mW = 25 • mY = 55 • Find mV K Y 55 M V 25 W 100 S
Example 2: Congruence Statement Finish the following congruence statement: ΔJKL Δ_ _ _ M J ΔJKL ΔNML L K N
Proof: Th(4-1) If 2 s of one Δ are to 2 s another Δ, then the third s are also . Given: B E A D Prove: C F A B C D F E
Statements • B E & A D • mB + mA + mC = 180 • mE + mD + mF = 180 • 3) mB + mA + mC = • mE + mD + mF • mB + mA + mC = • mB + mA + mF • mC = mF • C F • Reasons • Given • Def. of Δ • Trans. • 4) Subs. • Subtr. • Def. of
Example • Proof: Given: GC GD CN DN Prove: ΔGCN ΔGDN G D C N
G Show all of the parts are given 3 sides given reflexive D C N given 3 angles given Thm 4-1