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### Course: High school geometry > Unit 1

Lesson 3: Translations# Translating shapes

Learn how to draw the image of a given shape under a given translation.

## Introduction

In this article, we'll practice the art of translating shapes. Mathematically speaking, we will learn how to draw the image of a given shape under a given translation.

A translation by $\u27e8a,b\u27e9$ is a transformation that moves $a$ units in the $x$ -direction and $b$ units in the $y$ -direction. Such a transformation is commonly represented as ${T}_{(a,b)}$ .

*all*points## Part 1: Translating points

### Let's study an example problem

Find the image ${A}^{\prime}$ of $A(4,-7)$ under the transformation ${T}_{(-10,5)}$ .

### Solution

The translation ${T}_{({-10},{5})}$ moves all points ${-10}$ in the $x$ -direction and ${+5}$ in the $y$ -direction. In other words, it moves everything 10 units

*to the left*and 5 units*up*.Now we can simply go 10 units to the left and 5 units up from $A(4,-7)$ .

We can also find ${A}^{\prime}$ algebraically:

### Your turn!

#### Problem 1

#### Problem 2

## Part 2: Translating line segments

### Let's study an example problem

Consider line segment $\stackrel{\u2015}{CD}$ drawn below. Let's draw its image under the translation ${T}_{(9,-5)}$ .

### Solution

When we translate a line segment, we are actually translating all the individual points that make up that segment.

Luckily, we don't have to translate

*all*the points, which are*infinite!*Instead, we can consider the endpoints of the segment.Since all points move in exactly the same direction, the image of $\stackrel{\u2015}{CD}$ will simply be the line segment whose endpoints are ${C}^{\prime}$ and ${D}^{\prime}$ .

## Part 3: Translating polygons

### Let's study an example problem

Consider quadrilateral $EFGH$ drawn below. Let's draw its image, ${E}^{\prime}{F}^{\prime}{G}^{\prime}{H}^{\prime}$ , under the translation ${T}_{(-6,-10)}$ .

### Solution

When we translate a polygon, we are actually translating all the individual line segments that make up that polygon!

Basically, what we did here is to find the images of $E$ , $F$ , $G$ , and $H$ and connect those image vertices.

### Your turn!

#### Problem 1

#### Problem 2

#### Challenge problem

The translation ${T}_{(4,-7)}$ mapped $\mathrm{\u25b3}PQR$ to an image. The image, $\mathrm{\u25b3}{P}^{\prime}{Q}^{\prime}{R}^{\prime}$ , is drawn below.

## Want to join the conversation?

- I dont understand that well without the graph(51 votes)
- I also don't understand this without a graph(33 votes)

- How do you construct a translation with a compass with a point away from the shape?(26 votes)
- i have the same question(0 votes)

- Geometry more like Geomystery because I have no idea what's going on (Joke, this is easy)(33 votes)
- I was confused on the last one. Like I moved it 4,-7 but it's still wrong. Can someone help me please?(12 votes)
- The issue is that the question asks you to go from the image back to the preimage. So if the translation from the preimage to the image is <4,-7>, then to go backwards from the image to the preimage, you have to go backwards along the vector <-4,7>.(33 votes)

- This should be less challenging(16 votes)
- without challenges you would be bored(6 votes)

- I need to understand problem 2 on translating line LM and NO(5 votes)
- Here is a strategy:

Move the green line onto the blue line so that you could see it overlapping it. Then move one point of the green line depending on the translation. In problem 2, the translation is (10,0), so it means that you have to move the point 10 units to the right, and 0 units up. Then do the same thing on the other point. Then you are done.(20 votes)

- I have no idea how to do a reverse translation...(6 votes)
- flip the signs, so -4 turns into +4 and 7 into -7(9 votes)

- I was confused on the direction(8 votes)
- I was confused about the direction my dad went.....
*italics*(4 votes)

- Does that mean we are mapping the original triangle in this question?(6 votes)
- Yes. As one can see, the question shows P'Q'R', and asks you to map PQR. Remember that P'Q'R' is read, "P prime Q prime R prime." "Prime" signifies that it is the IMAGE, or result, of a transformation. So, it wants you to map the original triangle.(4 votes)

- This H.S. Geometry translation helped w/ my spiral translation. My question is: "All of me united is 11 x 6. But when I'm squared my table feet are shown. What am I ?

Ans. Chain squared(6 votes)- Mind explaining, I don't really understand sorry!(3 votes)