Similar figures worksheets

Two shapes are similar when one is a scaled copy of the other: same angles, sides all multiplied by the same number. These free printable worksheets give both figures with one side missing, and finding the scale factor first is what makes the rest easy.

Similar figures
Similar figures worksheet — Whole-number scale factors, free printable with answer key

The answer key prints on a separate page.

What's on this sheet

The whole method is two steps. Find a pair of sides that correspond and divide to get the scale factor — 18 against 9 is a factor of 2 — then apply it to the side you want. A child who does it in that order never has to set up a proportion at all, and the arithmetic stays inside the times tables.

Why this sheet works

Which sides correspond is the part that goes wrong. Shapes are drawn in the same orientation here so the pairing is readable, but it is still worth saying out loud: the long side matches the long side. Once figures start being rotated, a child who has been checking the pairing has something to fall back on.