Triangle Theorems and Congruent Triangles
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Learn about the angle sum and exterior angle theorems, as well as how to prove congruent triangles using SSS, SAS, ASA, AAS, and HL postulates.
Triangle Theorems and Congruent Triangles
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Presentation Transcript
Unit 4 TRIANGLE FUN
I can use the angle sum theorem • I can use the angle sum theorem • I can the exterior angle theorem • I can the exterior angle theorem Learning Targets Lesson 4-1
sum angles 180°
30° m∠1 = 28° m∠1 = 120°
58° 32° 32° 58° m∠1 = 56° m∠2 = 56° m∠3 = 74°
remote interior exterior not
exterior angle sum remote interior angles m∠1 = m∠A + m∠B
2x + 95 = 145 2x = 50 x = 25
140° 65° 40° 75° 115°
55° 55° 70°
125° 55° 95°
ASSIGNMENT: 4-1Worksheet
4.2 Congruent Triangles Learning Target: • I can name and label corresponding parts of congruent triangles.
vertices A B C
size shape
Angle Measure Betweenness Collinearity Distance
m∠A = m∠J JK AB = m∠B = m∠K BC = KL m∠L JL m∠C = AC = Match up the letters in the same “position” AND look at the ‘tick marks’ in the picture! Match the congruent pieces!
I can recognize and use the SSS, SAS, ASA, AAS, and HL Postulates to see if triangles are the same. Lesson 4.3
CAN’T USE!!! 40 40 50 50
CAN’T USE!!! 7 7 6 6 40° 40°
SAS ∆DNV ≅ ∆BCX
SSS ∆TRS ≅ ∆SUT
HL ∆JKL ≅ ∆MNP
AAS ∆NJK ≅ ∆LMK
Your turn! Try e-h! SAS ∆CDA ≅ ∆BDA
ASA ∆RST ≅ ∆UVT
AAS ∆RUT ≅ ∆RST
SAS ∆FJH ≅ ∆GHJ
A M R C W G MG ≅ AC
D X G K Y Z YZ ≅ DK
D A E F B C ∠B ≅ ∠E or ∠C ≅ ∠F
ASSIGNMENT: “Swimming through triangles” worksheet, both sides (Pages 3 – 4)
PROOFS! Lesson 4.4
TS ≅ TS Given Given Reflexive ∆RST ≅ ∆UTS SSS
US ≅ US Given Given Def’n of angle bisector ∠RSU ≅ ∠TSU Reflexive SAS ∆RSU ≅ ∆TSU
BD ≅ BD Given Given Reflexive SSS ∆ABD ≅ ∆CBD CPCTC ∠A ≅ ∠C
DF ≅ DF DG ≅ FE Given Given Reflexive AIA ≅↔ || lines ∠EDF ≅ ∠GFD AAS ∆EDF ≅ ∆GFD CPCTC
BC ≅ BC Given Given Reflexive HL ∆BAC ≅ ∆BDC CPCTC ∠A ≅ ∠D
BC || AD BD ≅ BD BC ≅ AD Your Turn… Given Given Reflexive AIA ≅↔ || lines ∠CBD ≅ ∠ADB ∆ABD ≅ ∆CDB SAS