Scale Factor Geometry Lesson

Image and Preimage

​

• Similar figures are figures that have the same shape.  

• They can be the same exact size, or one can be larger than the other.

​

​Similar Shapes

Multiple Choice

What are similar shapes?

• Are shapes that have the same shape, but not necessarily the same size.

• Compares the sizes of the parts of the scale drawing to the actual sizes on the original object.

• They are sides that are in the same position in different plane figures. 

• They are sides that have different ratios.

Drag and Drop

Both similar and congruent figures have the same ​

Placeholder

.

But, congruent figures also have the same ​

Placeholder

.

Drag these tiles and drop them in the correct blank above

shape

size

length

height

Scale Factor

​Go to the Edpuzzle video on Scale Factor in your Google Classroom

Multiple Choice

What is a scale factor?

• Shapes that have the same shape, but not necessarily the same size.

• A ratio/number that compares the sizes of the parts of the scale drawings.

• They are sides that are in the same position in different plane figures.  

• The length of a side of a similar figure.

Multiple Choice

Solve for X.

• 2 ft

• 3 ft

• 4 ft

• 6 ft

Multiple Choice

What is the scale factor of these similar shapes?

• 10

• 7

• 9

• 11

Multiple Choice

The pair of figures is similar. Find the missing side.

• x = 9

• x = 28

• x = 7

• x = 63

Multiple Choice

The following shapes are similar, the smaller one is the original shape, what is the scale factor?

• 8:12

• 3:2

• 4:8

• 6:12

Multiple Choice

Use your knowledge of similar shapes, to solve for X. 

• 35 cm

• 10 cm

• 42 cm

• 28 cm

Transformation

​Go to the Edpuzzle video on Scale Factor in your Google Classroom

Multiple Choice

The original figure prior to a transformation.

• Pre-image

• Image

Multiple Choice

The result of a transformation.

• Pre-image

• Image

Multiple Choice

Determine where T' would be if you translated T 3 units to the right and 6 units up.

• (5, 1)

• (2, -5)

• (-1, 1)

• (8, -2)

Multiple Choice

Write the rule for this translation:
Slide 3 up and 2 right

• (x, y)---->(x + 3, y + 2)

• (x, y)-----> (x+2, y + 3)

• (x, y)----> (x - 2, y + 3)

Multiple Choice

Identify the transformation from ABC to A'B'C'.

• (x+8, y+4)

• (x-8, y-4)

• (x+4, y+8)

• (x-4, y-8)

Graphing

Plot A' after translating Point A (2, 6) using the rule:

(x, y) ---> (x - 3, y + 2).

Drag and Drop

In this figure, triangle TRS is the ​

Placeholder

, triangle T'R'S' is the ​

Placeholder

and a(n) ​

Placeholder

occurred.

Drag these tiles and drop them in the correct blank above

pre-image

image

enlargement

reduction

spin

flip

Multiple Choice

Quadrilateral NDPM was dilated to quadrilateral N'D'P'M'. What was the scale factor for this dilation?

• 2

• 3

• 1/3

• 1/2

Multiple Choice

The point (8, 12) was dilated to become point (2, 3). What was the scale factor

• ½

• ¼

• 4

• 2

Multiple Choice

State the coordinates of point C after a dilation with a scale factor of 1/2 and center about the origin.

• (-3, -2)

• (3, -2)

• (-12, -8)

• (-2, -3)

Multiple Choice

State the coordinates of point A after a dilation, with the center of dilation at (0,0), and a scale factor of 2.

• (2,2)

• (8,8)

• (0,12)

• (4,12)