Roots of Reason
Roots of Reason
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two questions, not one
Anchor Chart · Grade 4 · 4.G.A.2

Classifying Triangles

Sort by side lengths. Sort by angles. Every triangle gets a name from both.
1Sort by Side Lengths
equilateralthree sides alikeisoscelestwo sides alikescaleneno sides alike
Tick marks show which sides match.
2Sort by Angles
acuteall angles under squarerightone square cornerobtuseone angle past square
The square corner is the one to look for.
3Both Names, Not One
by sidesisoscelesby anglesright
Every triangle answers to both questions.
One name from sides, one from angles.
4Measure. Do Not Eyeball.
6 cm6 cm6.5 cmnot equilateralisosceles
This one looks even. It is not.
Read the measurements, not the picture.