Big Idea:

Big Idea 5

SSS, SAS, and ASA are sufficient criteria to justify triangle congruence.

1 week

Evidence of Understanding

  • justify the minimum requirements that show two triangles are congruent
    • describe how a sequence of transformations demonstrates the mapping of corresponding sides for two congruent figures
      • use notations to signify the corresponding parts
    • make conjectures about the minimum corresponding parts of the triangle needed to construct a congruent triangle
      • experiment with constructions to support these claims
      • give examples, non examples, or counterexamples about these claims
      • use transformations of these parts to support their claim that the triangles are congruent
    • justify that when all corresponding sides of two triangles are congruent (SSS) there is sufficient evidence to show that these two triangles are congruent
      • use tools to construct a copy of a given triangle using side measurements
    • justify that when two corresponding sides and the included angle are congruent (SAS) there is sufficient evidence to show that these two triangles are congruent
      • use tools to construct a copy of a given triangle using two side measurements and the included angle
      • establish the the minimum criteria necessary to prove two right triangles are congruent using the hypotenuse and a leg (HL)
    • justify that when two corresponding angles and the included side of two triangles are congruent (ASA) there is sufficient evidence to show that these two triangles are congruent
      • use tools to construct a copy of a given triangle using two angle measurements and the included side
      • justify why the angle has to be the included angle of the corresponding sides using constructions (SSA does not work)

Develop conceptual understanding:

SSS, SAS, HL, ASA

Supporting terms to communicate:

included angle/side, construct, copy, corresponding parts, preserve, congruent, sequence of transformations, rotate, reflect, translate, parallel, perpendicular
Core Resource

No Core Resource for this Big Idea.

Consider using the Instructional Routines linked below for teaching towards this Big Idea.