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Learning Goal

‹2 of 3 in this cluster›

Draw geometric shapes with given conditions

Start lessonBegins with Triangle conditions · Slides

Teacher tools for this standard

Lesson Plan · Guided Notes · Exit Ticket · Re-teach · Homework

Lesson Plan →Objectives, pacing and practice, built from this lesson's brief.
Guided Notes →One page your students fill in and keep.
Exit Ticket →Three items at the end of class. No student accounts.
Re-teach →After an exit ticket: who missed what, and what to do tomorrow.
Homework →Assign practice; it grades itself.

7.G.A.2

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What you'll learn

Draw geometric shapes with given conditions using freehand sketches, ruler and protractor, and dynamic geometry tools.
Construct a triangle given three side lengths (SSS) and determine whether the given lengths can form a triangle using the triangle inequality.
Construct a triangle given two sides and the included angle (SAS) and recognize that these conditions determine a unique triangle.
Construct a triangle given two angles and the included side (ASA) and recognize that these conditions determine a unique triangle.
Explain why three angle measures alone (AAA) do not determine a unique triangle, identifying that infinitely many similar triangles satisfy the same angle conditions.
Analyze ambiguous triangle conditions (SSA) and determine whether zero, one, or two triangles can be formed, supporting conclusions with constructed examples.

Slides

Step through the lesson, or watch it as a narrated video • 2 slide decks

1

Triangle conditions

✓ Start here

2

SAS ASA aaa ssa

Practice

Try it on your own

Exercise

Practice problems, checked as you go

Animated Videos

Short animated explanations of the key idea • 5 animated videos

One Figure, Infinitely Many, or None: What Conditions Determine

Open on YouTube

Three Side Lengths: Exactly One Triangle, or None

Open on YouTube

Two Sides with the Angle Between, Two Angles with the Side Between

Open on YouTube

Three Angles Fix the Shape, Not the Size

Open on YouTube

Two Sides and a Non-Included Angle: Zero, One, or Two Triangles

Open on YouTube

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