---
title: "Reflection and Translation on a Grid"
description: "Identify, describe, and represent the position of a shape following a reflection or translation using appropriate language; know that the shape has not changed"
canonical: https://lightmysky.com/learn/mathematics/reflection-and-translation-on-a-grid-mt_efOeaGFyGM
source: https://lightmysky.com/learn/mathematics/reflection-and-translation-on-a-grid-mt_efOeaGFyGM.md
retrieved: 2026-09-02
---

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# Reflection and Translation on a Grid

Identify, describe, and represent the position of a shape following a reflection or translation using appropriate language; know that the shape has not changed

Subject: Mathematics · Area: Geometry · Ages 9 to 10
Page: https://lightmysky.com/learn/mathematics/reflection-and-translation-on-a-grid-mt_efOeaGFyGM

## Ready when they can

- Reflect a triangle in a vertical mirror line on a coordinate grid and state the new coordinates
- Translate a shape 3 units right and 2 units up and describe the movement
- Explain that a reflected/translated shape is congruent to the original

## Lesson: Reflection and Translation on a Grid

You already know how to flip a shape over a line and how to slide it across a grid. Now you will do both of these on a coordinate grid, and describe the shape's new position using coordinates.

*(drawing: This triangle is about to be reflected and translated on a grid.)*

**Example.** Triangle ABC has corners at (2, 1), (5, 1), and (3, 4). Reflect it in the vertical line x = 0. Each y-coordinate stays the same, but each x-coordinate flips sign: A' (-2, 1), B' (-5, 1), C' (-3, 4).

**Example.** A square's corner starts at (1, 2). It slides 3 units right and 2 units up. Add 3 to the x-coordinate and 2 to the y-coordinate: (1 + 3, 2 + 2) = (4, 4).

After a reflection or a translation, the shape is congruent to the original. Congruent means exactly the same size, with the same angles, just sitting in a new spot on the grid. Nothing stretches, shrinks, or bends. Only the position changes.

**Recap.** Reflecting or translating a shape only changes its position on the grid. The shape itself, its size and its angles, never change.

## Practice

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

## Needs first

- [Lines of symmetry](https://lightmysky.com/learn/mathematics/lines-of-symmetry-mt_hR2Y7NhMSY)
- [Coordinates (age 8+)](https://lightmysky.com/learn/mathematics/coordinates-age-8-mt_i5_HnoFOYw)
- [Transformations on a grid](https://lightmysky.com/learn/mathematics/transformations-on-a-grid-mt_SH7QgFl8-v)
- [Describing Movements](https://lightmysky.com/learn/mathematics/describing-movements-mt_Uq5vYqboCR)

## Opens up

- [Translating and reflecting shapes](https://lightmysky.com/learn/mathematics/translating-and-reflecting-shapes-mt_lxaM6iVpdr)