Figure perimeterTriangles
Name: Date:
Add every side. All lengths are in centimeters.
1 cm
2 cm
3 cm
4 cm
5 cm
6 cm
7 cm
8 cm
Perimeter of a triangle worksheets
A triangle's perimeter is the distance around it: add the three sides. These free printable worksheets label every edge, including the slanted ones, so all three numbers count toward the answer.
If they get stuck
Perimeter of a triangle
The answer key prints on a separate page.
What's on this sheet
This is the triangle taken out of the mixed perimeter page, which rotates through triangles, parallelograms, trapezoids, and rectangles. On its own it is a clean three-number addition, which is where a child starting perimeter should begin.
Why this sheet works
Every side carries its own number — the opposite of the area sheets, where slant sides are deliberately left blank. Here a blank edge would make the figure unanswerable, so all three are printed, and the triangle is drawn to match them: sides of 14, 13, and 17 are drawn as exactly that triangle.
How this one works
One question from a sheet like this one, worked a step at a time — with a sentence saying what just happened and why.
Perimeter of a triangle, step by step