Pre-Algebra Demystified

SOLUTION

x

15

¼

26

75

75x¼ 15  26 Cross multiply

75x¼ 390

75 x

75

¼

390

75

Divide by 75

x¼ 515 or 5: 2

PRACTICE

Find the value of x:

1.

3

4

¼

24

x

2.

5

x

¼

35

42

3.

12

7

¼

x

56

4.

25

8

¼

x

56

5.

x

9

¼

22 : 75

63

ANSWERS

1. 32

2. 6

3. 96

4. 175

5. 3.25

Word Problems

In order to solve word problems using proportions:

 Step 1 Read the problem.

 Step 2 Identify the ratio statement.

 Step 3 Set up the proportion.

 Step 4 Solve for x.

156 CHAPTER 8 Ratio and Proportion