Name a triangle by counting how many of its three sides match: three equal is equilateral, exactly two is isosceles, none is scalene. These free printable worksheets drill that one naming.
If they get stuck
The answer key prints on a separate page.
The standard asks children to name a triangle two independent ways, and the mixed classifying page hands both at once. This sheet takes just the side naming, so a child settles equilateral, isosceles, and scalene before the angle names are added to the mix.
All three side lengths are printed and the triangle is drawn to match them, so an isosceles triangle genuinely has two equal sides on the page and a scalene one has three different lengths. A figure that reads 8, 8, 5 while looking lopsided would teach a child to distrust the picture, which is the last thing a naming sheet should do.
One question from a sheet like this one, worked a step at a time — with a sentence saying what just happened and why.
Classify triangles by sides, step by step