Use cross products to see if each pair of ratios forms a proportion. Replace each box with = or ≠.
1.
7/5 ? 15/10
=
≠
2.
6/8 ? 15/20
=
≠
Solve each problem.
3.
2/3 = 1.2/x
x = 18
x = 1.8
x = 0.2
x = 10
4.
4/5 equals 8/x plus 2
x = 4
x = 9.5
x = 2
x = 8
Create a proportion and solve.
5.
A recipe uses 3 cups of flour to make 48 cookies. How much flour is needed to make 72 cookies? (1 point)
3/48 = 72/x, x = 1,152 cups
3/48 = x/72, x = 4.5 cups
3/48 = x/72, x = 2 cups
x/48 = 3/72, x = 2 cups
Here are my answers. Are they correct? Thanks!
1. ≠
2. =
3. 1.8
4. x = 8
5. 3/48 = x/72, x = 4.5 cups
1. ≠
2. =
3. 1.8
4. x = 8
5. 3/48 = x/72, x = 4.5 cups
100%
1. ≠
2. =
3. 1.8
4. x = 45
5. 3/48 = x/72, x = 4.5 cups
"shawn mendes is bae" is correct, except now the answer to 4 is x = 45
:) the question changed ig
3. (A) x=18
4. (D) x=154
5. (B) 30
Yay! All are right!
I am taking the test right now, and I am really smart, So here are the right answers.
Lesson 2: Proportions, Connections Academy
******* Math Grade 8 A Unit 5: Applications of Proportions
Multiple Choice
Use CROSS PRODUCTS to see of each pair of ratios forms a proportion. Replace each box = or ≠.
1. 7/5 ? 15/10
Answer: ≠
Explain: Use CROSS PRODUCTS! 7*10 is equal to 70 and 5*15 is equal to 75. Therefore, the two products do NOT form a proportion.
2. 6/8 ? 15/20
Answer: ≠
Explain: Use CROSS PRODUCTS! 6*20 is equal to 120 and 8*15 is also equal to 120. Therefore, the two products are proportions.
Solve each problem.
3. 2/3 = 1.2/x
Answer: x = 1.8
Explain: We now know that we had to use cross products before. We can still use cross products for this equation. We know that 3*1.2 is equal to 3.6, but we don't know what 'x' is. In order to find out what 'x' is, we have to divide 3.6 by 2 sense that is the only number we have not used yet. 3.6/2 is 1.8. That is how I got the answer of '1.8'.
4. 4/5 = 8/x + 2
Answer: x = 8
Explain: We can still use the cross products method with this. We know that 4*5 is equal to 40, but we don't know what 'x + 2' is. Now we have to find out what times 4 gives us 40, then we have to subtract 2 from that number because we want to dot he opposite of the operation given which is subtraction. So 4*10 is 40, but we are not done yet --- 10 is the number multiplied by 4 to get us 40, so 10 - 2 is 8. That is how I got the answer of 8.
Create a proportion and solve.
5. A recipe uses 3 cups of flour to make 48 cookies. How much flour is needed to make 72 cookies?
Answer: 3/48 = x/72, x = 4.5 cups
This one is pretty self explanatory, so I will just post the answer choices and you will see what I mean.
A. 3/48 = 72/x, x = 1,152 cups - The amount of cups needed won't even be over 100.
B. 3/48 = x/72, x = 4.5 cups - This is the only answer choice that makes sense.
C. 3/48 = x/72, x = 2 cups - The amount of cups needed is already 3 in the question.
D. x/48 = 3/72, x = 2 cups - The amount of cups needed is already 3 in the question.
This leaves us with the only answer choice that makes sense; B. 3/48 = x/72, x = 4.5 cups
You're very welcome!
But YOU did these problems! :-)
I hereby dub thee- CORRECT!
Wait I got different ones from three down
I love how some of these are super positive and everyone is happy and the next thing you know, you check another question, and everyone is ranting and yelling at each other lmaO
Hi,
Just came to check in and I am SOOOOO proud of everyone for being supportive to each other and not getting off topic...
Keep it Up!!!
HelpGirl101