Question

this process can also be used when one side of the equal sign is not in fraction form.
example 2: find ( x ) when ( 27 = \frac{x}{3} )
solution:
step 1. the number 27 is the same as ( \frac{27}{1} ). so, place a 1 under the 27 to get:
( \frac{27}{1} = \frac{x}{3} )
step 2. cross multiply and divide as above ( \frac{27}{1} = \frac{x}{3} ) to solve.
so: ( x = 27 \times 3 div 1 )
( x = 81 )
assignment 2 – cross multiply and divide
solve for the missing term by using cross multiply and divide, as described on the section above. if necessary, round answers to one decimal place. show your work.

1. ( \frac{x}{7} = \frac{4}{35} )
2. ( \frac{2}{9} = \frac{x}{27} )
3. ( \frac{3}{18} = \frac{25}{x} )
4. ( \frac{3.2}{x} = \frac{16}{4} )
5. ( \frac{x}{6} = \frac{0.5}{17} )
6. ( \frac{25}{x} = \frac{40}{200} )

Explanation:

Problem 1:

Step1: Cross multiply to isolate x

$x = \frac{4 \times 7}{35}$

Step2: Calculate numerator then divide

$x = \frac{28}{35} = 0.8$

Problem 2:

Step1: Cross multiply to isolate x

$x = \frac{2 \times 27}{9}$

Step2: Calculate numerator then divide

$x = \frac{54}{9} = 6$

Problem 3:

Step1: Cross multiply to isolate x

$x = \frac{25 \times 18}{3}$

Step2: Calculate numerator then divide

$x = \frac{450}{3} = 150$

Problem 4:

Step1: Cross multiply to isolate x

$x = \frac{3.2 \times 4}{16}$

Step2: Calculate numerator then divide

$x = \frac{12.8}{16} = 0.8$

Problem 5:

Step1: Cross multiply to isolate x

$x = \frac{0.5 \times 6}{17}$

Step2: Calculate numerator then divide

$x = \frac{3}{17} \approx 0.2$

Problem 6:

Step1: Cross multiply to isolate x

$x = \frac{25 \times 200}{40}$

Step2: Calculate numerator then divide

$x = \frac{5000}{40} = 125$

Answer:

1. $x = 0.8$
2. $x = 6$
3. $x = 150$
4. $x = 0.8$
5. $x \approx 0.2$
6. $x = 125$