LESSONNEW
Dilations
Save
Copy and Edit
INSTRUCTOR-LED SESSION
Start a live lesson
ASYNCHRONOUS LEARNING
Assign homework
13 slides PreviewShow answers
  • Slide 1
    Report an issue

    Dilations

    December 4, 2020

  • Question 2
    Ungraded
    300 seconds
    Report an issue
    Q.

    On Tuesday we were feeling pretty down and out about school and life. How are you doing today? Have things changed (for better or for worse?) at all for you?


    Is there anything that I can do (other than not assigning any work) that would help make your world a little brighter?


    *Remember: No one else will see these responses, they are just for you to talk to me*

  • Question 3
    60 seconds
    Report an issue
    Q.

    Warm-up: What does the scale factor do in a dilation?

    answer choices

    Tells you how much the image grows or shrinks

    Tells you what the center of dilation is

    There's not enough information here to answer this

    Nothing, it's unnecessary information

  • Slide 4
    Report an issue

    Scale Factors

    What do they really do?

  • Slide 5
    Report an issue

    Scale Factors are just as they sound

    • Factors (multipliers) that scale (change the size of) a shape

    • Scale factors can do one of two things: grow or shrink an object

    • A scale factor larger than one (>1) makes an object get larger --> could be a fraction or a whole number

    • A scale factors smaller than one (<1) makes an object get smaller

  • Question 6
    120 seconds
    Report an issue
    Q.

    Which scale factors would increase an image?

    answer choices

    32\frac{3}{2}

    12\frac{1}{2}

    3.53.5

    21\frac{2}{1}

    5

  • Question 7
    120 seconds
    Report an issue
    Q.

    Which scale factors shrink an image?

    answer choices

    0.50.5

    34\frac{3}{4}

    11

    21\frac{2}{1}

    32\frac{3}{2}

  • Question 8
    120 seconds
    Report an issue
    Q.

    What are the properties of dilations?

    answer choices

    Changes the size of an object

    Changes the shape of an object

    Changes one side but not the others

    Changes all the sides equally

    Changes angle measures

  • Slide 9
    Report an issue

    What happens if you aren't given the scale factor?

    • Set up a proportion

    • Solve for the missing side

  • Slide 10
    Report an issue

    But...what's a proportion?

    A proportion is a ratio (fraction) that compares the corresponding pairs of sides

  • Slide 11
    Report an issue

    Proportion Example

    The missing side, EF, can be found by setting up a proportion between the pairs of corresponding sides.
    We know AB and DE are corresponding, and we know BC and EF are corresponding. So our proportion will be

     ABDE = BCEF\frac{AB}{DE}\ =\ \frac{BC}{EF}  which is  53 = 2x\frac{5}{3}\ =\ \frac{2}{x}  

  • Slide 12
    Report an issue

    How do we solve a proportion now?

    • Set up your proportion

       53 = 2x\frac{5}{3}\ =\ \frac{2}{x}  

    • Cross multiply (just like with regular fractions)   5x = 6

    • Solve for x (divide both sides by 5)  x = 65 = 1.2x\ =\ \frac{6}{5}\ =\ 1.2  

  • Slide 13
    Report an issue

    There is a proportions practice sheet in Google Classroom

    Please go work on that

    Email me if you have any questions :)

Report an issue
Why show ads?
Report Ad
Lessonsnew
Enter Code