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### Course: Geometry (all content) > Unit 10

Lesson 9: Old transformations videos# Performing translations (old)

An older video where Sal uses the interactive widget to find the image of a rectangle under a translation. Created by Sal Khan.

## Want to join the conversation?

- what is the difference between translation and reflection?(7 votes)
- Translation: moving the origin of a polygon, but retaining the direction of each axis.

Reflection: a polygon's "mirror image" over a specified line.

=D(8 votes)

- can polygons be circular(4 votes)
- No way... a polygon is defined as what? How about a circle? You can bend into a polygon a circular wire; but geometrically, the two concepts are as different as night and day! :-)(0 votes)

- Do polygons have curves?(5 votes)
- I want to practice the skills and watch the videos only when i need help. Where are the exercises?(3 votes)
- How would you define a regular polygon?(2 votes)
- Regular Polygon :

If all angles are equal and all sides are equal, then it is a regular polygon (otherwise it is "irregular").(3 votes)

- i couldnt load the video(2 votes)
- Try using Chrome if you were using Internet Explorer.(2 votes)

- Is a polygon a four sided shape(2 votes)
- A polygon is any closed shape with any number of straight, equal, sides. A quadrilateral has 4 sides.

Hope this helps!(2 votes)

- How would one describe a translation without a coordinate graph given, or coordinate points given for the vector? Also, would you use compass directions to describe the translation?(2 votes)
- Do translations have to be on the coordinate plane?(2 votes)
- Good question.

A translation occurs anytime a "preimage" is shifted up/down and left/right to a new location.

It's easiest to track a translation on a coordinate plane because we can make sure all corners are shifting the same numerical value.

However, you can translate a doodle on a blank piece of paper simply by recreating that exact doodle on another location on your paper - maybe down to the right.(1 vote)

- How to find if it is a rigid motion(2 votes)
- If the figure stays the same shape and size then its a rigid motion. So any rotation, translation, and reflection are rigid motions.(1 vote)

## Video transcript

What is the image of the polygon
below after the translation is capital T with the
subscript 5 comma 2? So that means let's translate
5 in the horizontal direction and 2 in the vertical direction. So let's do that. So I'm going to focus on
this point right over here. So that point is at
the point 3 comma 3. If I want to translate five
in the horizontal direction, the x value is
going to get to 8. So the x value is
going to 1, 2, 3, 4, 5. And then we want to
increase the y value by 2. 1, 2. Let's check our answer. Let's do a couple more of these. That was lot of fun. So here we need to
shift it by negative 8 in the horizontal direction. So this one right over
here, it's x value is 0, so we need to go essentially
negative 8, negative 1, negative 2, or we move to the
left 1, 2, 3, 4, 5, 6, 7, 8. And then we have to
move it down by 2. So we have to move
down 1, move it down 2. And we're done.