Drawing triangles with given conditions

Can you draw a unique triangle with the given information, or several different ones? We look at six different situations:

• an equilateral triangle (e.g. all angles 60 degrees)
• three angles are given
• two angles and a side between them are given
• two sides and an angle between them are given
• three sides are given
• three sides are given, but something special happens - we get no triangle!

I use a ruler, a protractor, and a compass to draw the triangles. Two of the situations are actually standard geometric constructions (equilateral triangle and a triangle with three given sides).

This lesson is meant for 7th grade math and matches the Common Core Standard 7.G.2.

See also

Drawing geometric shapes with given conditions — video lesson

Math Mammoth Geometry 3 — a self-teaching worktext with explanations & exercises (grades 4-5)

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