Question

1. Which ratios form a proportion?
A. 4/9, 12/25
B. 3/7, 18/42
C. 5/11, 20/45
D. 5/8, 15/25

2. Which ratio forms a proportion with 18/30?
A. 20/35
B. 50/90
C. 36/48
D. 60/100

3. Which proportion has cross products of 5× 24 and 8 ×15?
A. 5/8 = 15/24
B. 5/24 = 8/15
C. 8/24 = 15/5
D. 15/8 = 5/24

Answer 1

Start with 1.
For each choice, reduce any fraction that is not reduced. If the fractions are equal, that is your answer.

Answer 2

really you cant just give me the answers right away

Answer 3

For example: 9:20's proportion can be 18:40.

Answer 4

For example, choice A.
Both fractions are already reduced. They are not equal, so A is not the answer.

Answer 5

Now try choice B.
3/7, 18/42
18/42 can be reduced.
Do you see a number that both 18 and 42 can be divided by?

Answer 6

Now look at B..

Answer 7

Exactly ^

Answer 8

ok

Answer 9

So, wouldn't 6 be a factor?

Answer 10

Yes. Divide the numerator and denominator of the right fraction of choice B by 6.
\(\dfrac{18}{42} = \dfrac{18 \div 6}{42 \div 6} \)
What do you get?

Answer 11

Exactly, @mathstudent55

Answer 12

never mind i did it myself and got a 100%

Answer 13

What'd you get for 2?

Answer 14

I dont understand that one that well.

Answer 15

2. Which ratio forms a proportion with 18/30?
A. 20/35
B. 50/90
C. 36/48
D. 60/100

Reduce the given fraction and reduce all the choices.

Answer 16

2. Which ratio forms a proportion with 18/30 = 3/5? Divide by 6
A. 20/35 = 4/7 Divide by 5
B. 50/90 = 5/9 Divide by 10
C. 36/48 = 3/4 Divide by 12
D. 60/100 = 3/5 Divide by 20

Now with all fractions reduced, which fraction in the choices equals 18/30?