Objectives
This lesson connects previous knowledge of angle and side measurement to concepts of
proving triangle congruence. Students will:
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show congruence of triangles using the definition.
show congruence of triangles using side-side-side (SSS), and introduce the idea
of side-angle-side (SAS), angle-angle-side (AAS), and angle-side-angle (ASA).
Essential Questions
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What does it mean for two shapes to be congruent, and how can we easily
determine whether two shapes are congruent?
Vocabulary
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Congruent: Having the same size and shape; congruent figures have
corresponding sides and angles congruent. [IS.1 - All Students]
Congruent Triangles: Two or more triangles with congruent corresponding
sides and angles; triangles that are identical; those with the same size and
shape.
Corresponding Angles: Angles in the same relative position in similar or
congruent figures.
Corresponding Sides: Sides in the same relative position in similar or
congruent figures.
Similar Triangles: Two or more triangles whose corresponding angles are
congruent. Congruent triangles are also similar triangles.
Duration
60–90 minutes [IS.2 - All Students]
Prerequisite Skills
Prerequisite Skills haven't been entered into the lesson plan.
Materials
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ribbon or string 12½ inches long, two per student
standard-sized paper or larger
markers and/or colored pencils
protractors or templates
ruler and pencil
identical sets of popsicle sticks where each set has three popsicle sticks of
different lengths, one or two sets per group
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Lesson 1 Exit Ticket (M-G-4-1_Lesson 1 Exit Ticket.doc and M-G-4-1_Lesson 1
Exit Ticket KEY.doc)