---
title: "Combining Simple Shapes"
description: "Compose simple shapes to form larger shapes (e.g. two triangles make a rectangle)"
canonical: https://lightmysky.com/learn/mathematics/combining-simple-shapes-mt_XjwUlmxdCT
source: https://lightmysky.com/learn/mathematics/combining-simple-shapes-mt_XjwUlmxdCT.md
retrieved: 2026-10-19
---

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# Combining Simple Shapes

Compose simple shapes to form larger shapes (e.g. two triangles make a rectangle)

Subject: Mathematics · Area: Geometry · Ages 5 to 6
Page: https://lightmysky.com/learn/mathematics/combining-simple-shapes-mt_XjwUlmxdCT

## Ready when they can

- Join two triangles to make a rectangle or larger triangle
- Use pattern blocks to fill a hexagon outline
- Create a picture or design by combining basic shapes

## Lesson: Combining Simple Shapes

You know shapes like triangles and squares. Take a rectangle. Cut it from corner to corner. You get two matching triangles. The cut edge is the long edge on each part.

*(drawing: Cut a rectangle like this one from corner to corner to make two matching triangles.)*

**Example.** Ben has a six-sided puzzle. It has six matching triangle pieces. They fill it with no gaps. A shape with six straight sides is called a hexagon.

Shapes can make a picture. A triangle on top of a square makes a house. The triangle is the roof. A triangle sail and a long hull make a boat. The hull is the boat's body.

Round edges leave gaps. A circle cannot press flat on a straight edge. That is why a circle cannot fill a rectangle corner.

**Tip.** Try turning a shape around. Sometimes a turned shape fits together better.

**Recap.** Small shapes can join together to make bigger, new shapes.

## Practice

18 questions on this page, each with its working shown.

## Needs first

- [2-D shapes](https://lightmysky.com/learn/mathematics/2-d-shapes-mt_KJeEeTutJI)
- [Comparing 2-D and 3-D shapes](https://lightmysky.com/learn/mathematics/comparing-2-d-and-3-d-shapes-mt_yGv8doDAmp)

## Opens up

- [Composing Shapes](https://lightmysky.com/learn/mathematics/composing-shapes-mt_MqqR7VUoz1)