bruh, like why tho, who decided i need to know this, im not gonna look at a pie and be like, Well theoretically if you look close enough then that slice is a 14 degree angle also its definitely not a realistic career to be a mathematician

You use it for more than a mathematician. You can use it to cut a sandwich cmon man

I'm extremely confused on problem 2.2 on finding the area of the triangle. It looks off and I got a total different answer which is 14 1/2. :(

For a triangle, the area is 1/2 bh. You always want the base and the height to be perpendicular to each other, so the base is 2 and the height is 5. You should never use a side that is at any angle that is not 90 degrees.

What are rigid transformations? And how do they work? what do we use them for irl?

Rigid transformations are transformations where angles and lengths of shapes are preserved. It is like taking the same exact shape or object and moving it by reflecting it or rotating it. We use rigid transformations everyday simply by picking up and placing items somewhere else. (Like if you were to pick up a pencil and move it beside you).

why do some people not get that the comments are sarcastic 💀💀

Well, Spock, it's because we actually have a bit of something called feelings.

Main content

High school geometry

Course: High school geometry > Unit 2

Lesson 1: Rigid transformations overview

Getting ready for transformation properties

Google Classroom

Finding missing triangle angle measures, area and perimeter, and angle measures on transversals help prepare us to learn the properties of transformations.

Let's refresh some of the earlier concepts that will come in handy as we dig deeper into transformations. Then we'll look ahead to how the idea will help us with transformation properties.

Finding missing angle measures in triangles

Practice

Problem 1

Find the value of $x$ ‍ in the triangle shown below.

x =

°

For more practice, go to Find angles in triangles.

Where will we use this?

When we can transform one figure onto another using only rigid transformations, the two figures are congruent. We'll use congruence along with other concepts, like the fact that the interior angle measures of a triangle sum to

180 °

, to find missing measurements.

We'll use this skill in the Find measures using rigid transformations exercise.

Finding area and perimeter

Practice

Problem 2.1

What is the area of the rectangle?

square centimeters

For more practice, go to Represent rectangle measurements, Area of triangles, and Find perimeter when given side lengths.

Where will we use this?

Rigid transformations preserve length, so we can use the measurements in a congruent figure to help us calculate the perimeter or area of another figure.

We'll use these skills in the Find measures using rigid transformations exercise.

Using angle measures from transversals

Practice

Problem 3

Below are two parallel lines with a third line intersecting them.

Label each angle with its angle measure.
You may use each label as many or as few times as you need.

For more practice, go to Angle relationships with parallel lines.

Where will we use this?

Rigid transformations preserve angle measure. The properties of angle measures on transversals will help us make sense of why translations and dilations take lines to parallel lines, but rotations and reflections usually don't.

Here are a couple of the exercises that build off of angle measures with transversals:

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parker
Posted a year ago. Direct link to parker's post “why do we need this in re...”
why do we need this in real life
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- SOCCERBOI#3
  Posted 10 months ago. Direct link to SOCCERBOI#3's post “cuz our teachers tell us ...”
  cuz our teachers tell us too
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computercat779
Posted 5 months ago. Direct link to computercat779's post “is it normal for my schoo...”
is it normal for my school to go Algebra 1, Geometry, then Algebra 2.
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- luca.e.kim
  Posted 5 months ago. Direct link to luca.e.kim's post “Yeah my school does that”
  Yeah my school does that
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angusjacobs
Posted a year ago. Direct link to angusjacobs's post “bruh, like why tho, who d...”
bruh, like why tho, who decided i need to know this, im not gonna look at a pie and be like, Well theoretically if you look close enough then that slice is a 14 degree angle

also its definitely not a realistic career to be a mathematician
Button navigates to signup pageComment on angusjacobs's post “bruh, like why tho, who d...”
(12 votes)
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- Lane Downing
  Posted a year ago. Direct link to Lane Downing's post “You use it for more than ...”
  You use it for more than a mathematician. You can use it to cut a sandwich cmon man
  Comment on Lane Downing's post “You use it for more than ...”
  (15 votes)
Dory
Posted 2 years ago. Direct link to Dory's post “I'm extremely confused on...”
I'm extremely confused on problem 2.2 on finding the area of the triangle. It looks off and I got a total different answer which is 14 1/2. :(
Button navigates to signup pageComment on Dory's post “I'm extremely confused on...”
(8 votes)
Answer
- David Severin
  Posted 2 years ago. Direct link to David Severin's post “For a triangle, the area ...”
  For a triangle, the area is 1/2 bh. You always want the base and the height to be perpendicular to each other, so the base is 2 and the height is 5. You should never use a side that is at any angle that is not 90 degrees.
  Comment on David Severin's post “For a triangle, the area ...”
  (15 votes)
@clementine09
Posted 3 years ago. Direct link to @clementine09's post “What are rigid transforma...”
What are rigid transformations? And how do they work? what do we use them for irl?
Button navigates to signup pageComment on @clementine09's post “What are rigid transforma...”
(8 votes)
Answer
- yashaa
  Posted a year ago. Direct link to yashaa's post “Rigid transformations are...”
  Rigid transformations are transformations where angles and lengths of shapes are preserved. It is like taking the same exact shape or object and moving it by reflecting it or rotating it. We use rigid transformations everyday simply by picking up and placing items somewhere else. (Like if you were to pick up a pencil and move it beside you).
  Button navigates to signup page
  (4 votes)
Ari Hudson
Posted 4 months ago. Direct link to Ari Hudson's post “Guys something i learned ...”
Guys something i learned recently that helps A LOT is basically yk how when rotating clockwise is negative and counterclockwise is positive, well if you are able to, just turn your screen. So say its positive 90 degrees, you flop your computer or tablet on its side and picture the numbers being in the right place. It basically shows you what its supposed to look like once it is already rotated. I hope this helps!!
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kie000wil
Posted 5 months ago. Direct link to kie000wil's post “This is hard for me, at l...”
This is hard for me, at least the angles and triangle area type deal. I did these in advanced 7th grade and we went so fast I didn't even have time to memorize it. Think i failed that unit too. :/ Yeah this is a little bit of a struggle.
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kai
Posted 3 months ago. Direct link to kai's post “why do some people not ge...”
why do some people not get that the comments are sarcastic 💀💀
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(1 vote)
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- Lincoln Earley
  Posted 2 months ago. Direct link to Lincoln Earley's post “Well, Spock, it's because...”
  Well, Spock, it's because we actually have a bit of something called feelings.
  Button navigates to signup page
  (5 votes)
Simum
Posted 2 years ago. Direct link to Simum's post “I do not quite understand...”
I do not quite understand this from the article, "The properties of angle measures on transversals will help us make sense of why translations and dilations take lines to parallel lines, but rotations and reflections usually don't."
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(3 votes)
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- fr33d0g
  Posted 2 years ago. Direct link to fr33d0g's post “Look at when you do a dil...”
  Look at when you do a dilation, or a transversal. Say a square with side AB. you will notice afterwards , in the new image of a transversal or dilation of side AB is parallel with the image that you dilated or transversed from. But.... if you do a reflection or a rotation, they will not be parallel anymore. They will cross at some point. Hope this helps.
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Jasean N
Posted 2 months ago. Direct link to Jasean N's post “man I feel like napping.”
man I feel like napping.
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