Name ____________________

Date __________________

 

Proportions to Determine Length

 

Lesson 1

 

Problem:

 Use a proportion to find the unknown length.

 

    

ED = 4

DC = 5

CE = 8

 

JI = 36

IH =

HJ = 72

Solution
Step 1:
  

Using the proportion, ED:JI = 4:36 = 1 : 9

 

Also, CE:HJ = 1 : 9

 

 

 

Solution
Step 2:
  

Applying the same proportion for DC:IH,

 

DC=5; DC:IH = 1 : 9

 

So, IH = 45

 

Answer: IH = 45

 

Try two practice problems:

 A.

UR = 6

RS = 18

ST = 3

TU = 21

 

DE = 2

EF = 6

FG =

GD =

 

B.  

 

ED = 5

DC = 6

CE = 8

 

JI = 25

IH =

HJ = 40

 



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