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## MAP Recommended Practice

### Course: MAP Recommended Practice > Unit 17

Lesson 3: Visualize ratios# Ratios with tape diagrams

In the video, we explore ratios, which compare two quantities. We learn to find missing values using given ratios and discover equivalent ratios by multiplying or dividing both parts by the same number. Key examples include quilts, paint mixtures, and spells cast by characters.

## Want to join the conversation?

- How do people use tape diagrams? What even ARE tape diagrams? 🤔🧐(1 vote)
- Hey Kendra! Tape diagrams are visual models that use rectangles to represent the parts of a ratio. Since they are a visual model, drawing them requires attention to detail in the setup. In this problem David and Jason have numbers of marbles in a ratio of 2:3. This ratio is modeled here by drawing 2 rectangles to represent David’s portion, and 3 rectangles to represent Jason’s portion. The rectangles are uniform in size and lined up, e.g., on the left hand side, for easy visual reference. The large bracket on the right denotes the total number of marbles David and Jason have (35). It is clear visually that the boys have 5 rectangles worth of marbles and that the total number of marbles is 35. This information will be used to solve the problem. Hope this helps.(2 votes)

- I don't get it when I do the steps it says I have the wrong answers in my questions what do I do?(0 votes)
- Use the hints and compare your result to what is in the hint. See what was done differently - that's likely where your error is.(2 votes)

- Is this basically like using LCD ( least common denominator)?(64 votes)
- i think its like GCF(9 votes)

- I have been stuck here for 40 hours now. please help me. I don't get ratios at all is there easier to do this?(25 votes)
- Ratios are numbers that are comparing to each other for example, ¨For every 2 lbs of black paint, you have 4 lbs of white paint or 2:4.

Hope this helps. :)(23 votes)

- IDK what Sal means from0:46

Somebody help!🆘(16 votes)- basically you divide(6 votes)

- they have a question on harry potter in the vid(15 votes)
- i need help with ratios tape diagrams(11 votes)
- What do you need help with?(3 votes)

- i understand when i watch the video but when i go to do the ACTUAL problem that i have to do its so confusing, can someone explain to me (the video) pleasee.(13 votes)
- I will answer the second one. So the starting ratio is 4 to 5 because Luna has 4 squares and Ginny has 5 so for every 4 that Luna has Ginny has 5. So if Luna casts 20 spells that means she did 4x5 with her 4. And just like multiplying fractions you have to do the same thing with the other number. So that means you multiply 5x5 for Ginny making her new number 25 so that means the new ratio is 20 to 25.(11 votes)

- Can you make 10:6 in to 1 and 2/3(7 votes)
- no because then you don't know what your ratio is(3 votes)

- In the Khan academy "Ratios with tape diagrams", I can't understand how to solve the problems,even though I've watched the videos hundreds of times. The questions of area are hard. Can you help me?(7 votes)
- area just means length times width(3 votes)

## Video transcript

- [Instructor] We're
told Kenzie makes quilts with some blue squares
and some green squares. The ratio of blue squares
to green squares is shown in the diagram. The table shows the number of
blue squares and the number of green squares that Kenzie
will make on two of her quilts. All right, this is the
table they're talking about. Based on the ratio,
complete the missing values in the table. So why don't you pause this video and see if you can figure it out. Well, first, let's think about the ratio of blue to green squares. So for every three blue squares or that seem a similar color,
for every three blue squares, we are going to have
one, two, three, four, five green squares. So the ratio of blue to
green is three to five, and so in quilt A, she
has 21 blue squares. So she has 21 blue squares. How many green squares would she have? Well, to go from three to 21, you have to multiply by seven, and so you would take five and
then multiply that by seven. So you'd multiply five
times seven to get to 35. As long as you multiply both
of these by the same number or divide them by the same number, you're going to get an equivalent ratio. So 21 to 35 is the same
thing as three to five. Now we have a situation in quilt B. They've given us the number of
green squares, so that's 20. Well, how do we get 20 from five? Well, we would multiply by four. So if you multiply the number
of green squares by four, then you would do the same thing for the number of blue squares. Three times four... Three times four is
going to be equal to 12. 12 blue squares for every 20
green squares is the same ratio as three blue squares for
every five green squares. Let's do another example. Here, we are told the following
diagram describes the number of cups of blue and
red paint in a mixture. What is the ratio of blue paint
to red paint in the mixture? So try to work it out. All right, so let's just see. We have one, two, three,
four, five, six, seven, eight, nine, 10... 10 cups of blue paint for every one, two, three,
four, five, six cups of red paint. So this would be a legitimate
ratio, a ratio of 10 cups of blue paint for every
six cups of red paint, but this isn't in I guess
you could say lowest terms or most simplified terms because we can actually divide
both of these numbers by two, so if you divide 10 by two, you get five. I'll do that in blue color, and if you divide six
by two, you get three. So one way to think about it
is for every five blue squares, you have three red
squares in this diagram, in this tape diagram
that's sometimes called, or you could say for every
five cups of blue paint, you have three cups of
red paint in our mixture, and you could even see that here. So three cups of red paint and one, two, three, four, five... And five cups of blue paint, and you see that again right over here. Let's do another example. Here, we're told Luna and
Ginny each cast magic spells. The ratio of spells Luna casts to spells Ginny casts is
represented in this tape diagram. All right, based on the
ratio, what is the number of spells Ginny casts
when Luna casts 20 spells? Pause this video to see
if you can work it out. All right, so let's
just see the ratio here. For every one, two, three,
four spells that Luna casts, Ginny casts one, two,
three, four, five spells. So the ratio is four to five, but if Luna casts 20 spells... So if a Luna casts 20 spells,
well to go from four to 20, we had to multiply by five, and so we would do the
same thing with the number of spells Ginny casts. You'd multiply that by five, so it's 25. So four Luna spells for every five Ginny
spells is the same thing as 20 Luna spells for
every 25 Ginny spells, and so how many spells does Ginny cast when Luna casts 20 spells? She casts 25, and we're done.