Lesson 4: 3.4 ASA / AAS & HL

Why doesn't AAA (Angle-Angle-Angle) guarantee that two triangles are the same size?

ASA
AAS
HL (Hypotenuse-Leg)

CCSS.G.CO.B.8

I DO: Model the remaining postulates, specifically showing why HL only works for Right Triangles.
WE DO: Tangram puzzle activities. Work together to form congruent shapes using different smaller pieces.
YOU DO: Match proofs and criteria on a guided assignment.
Complete the "toolbox" of congruence verification methods.
DOK 2-3

Extension (High): Introduce more complex diagrams where students have to find "hidden" congruent parts (like shared sides)

Formative Assessment

Tangrams sets
Khan Academy right triangle modules