Corresponding Parts/Scale Factor

What are corresponding parts?

• When part of an original figure matches up with part of a copy, we call them corresponding parts. 

• These could be points, segments, angles, or distances.

Whole Class Example

What letters corresponds to the line AC?
What point corresponds to the point B?
What angle corresponds to the

Multiple Choice

What are corresponding parts?

• lines, points, and angles that are the same value or place on a shape

• parts of a square

• parts of a triangle

• another word for the perimeter of a shape

Multiple Choice

Find the corresponding part to point B.

• Point Z

• Point C

• Point Y

• Point X

Multiple Choice

Find the corresponding part to line segment ML

• Line Segment ST

• Line Segment JK

• Line Segment RS

• Line Segment UT

What is scale factor?

• To create a scaled copy, we multiply all the lengths in the original figure by the same number. 

• The number you multiply by is the scale factor

• You can find the scale factor by using ratios

• The scale factor is the ratio of corresponding side lengths

Scale Factor Whole Class Example 

• What is the scale factor from shape A to shape B?

• Find the corresponding sides

• Scale factor = new/original

• Reduce

Multiple Choice

Find the scale factor

• 1/2

• 2

• 3

• 1/3

Whole Class Example: Finding Scale Factor and Missing Number 

• locate corresponding side lengths

• look for relationships between their numbers

• How many centimeters is the side length GF?

• What is the scale factor?

Multiple Choice

How long is the side length GE?

• 7c

• 35 cm

• 28 cm

• 42 cm

Multiple Choice

How long is side length s?

• 15

• 12

• 9

• 3