Ratios 05:06 minutes

Video Transcript

Transcript Ratios

In her latest attempt to get internet famous, Leelee has decided to start her own online Food Vlog Channel... the FOOD QUEEN EXTREME! Leelee isn't exactly an expert chef, but who needs cooking skills when you've got the recipe for using perfect ratios! Let's take a look at what Leelee is making first: Major League Cheesy Potatos. The recipe calls for 3 parts potato for every 1 part cheese. The relationship between the amount of potatoes in her recipe and the amount of cheese is called a ratio. We can write it using the word 'to' like this, or using a colon like this, or as a fraction like this. No matter how we write it, each of these ratios is read as "3 to 1." The meaning of the numbers, and their order, is given to Leelee in the recipe. Potatoes first, followed by the cheese. But if Leelee makes a mistake, and flips the ratio. Now the ratio is one part potato for every three parts cheese! A potato to cheese ratio of 1 to 3 would be crazy cheesy! This is why with ratios, order matters. It's just like with fractions: three over one is not the same as one-third. Ok, that was a great recipe for people who love cheesy ballpark food, but up next is something on the lighter side. Yoga-Berry Banana Smoothies! The recipe calls for 4 parts strawberry for every 3 parts banana. But this recipe only works for one person. How does Leelee blend for more than one? We've already seen a few ways to write ratios. Now let's see how we can use a table to organize our information. We know that for every 4 parts strawberry, we need 3 parts banana. How about smoothies for two? If we double the parts of strawberry, we’ll have 8 parts strawberry, and we’ll need 6 parts of banana. And for three people? That’s a ratio of 12 parts strawberries to 9 parts bananas. We know the perfect 4 to 3 ratio is still in the smoothie, because if we write the ratios as fractions, the fractions are equal. 12 over 9 reduces to 4 over 3. Can Leelee make an extreme smoothie for a yoga class of 10 people? I think we're gonna need a bigger blender! The last recipe on Leelee's list is for Chew-Mocha Brownies.
It features three parts caramel for every five parts chocolate. We can represent this relationship in yet another way: a tape diagram. In this diagram, each of the small rectangles represents one part of the whole. This shows the ratio of caramel to chocolate as 3 to 5. But how can we use the diagram to help us double Leelee's recipe? Simply by changing the value of each rectangle from 1 to 2, the top 3 rectangles now represent 6 parts caramel, and the 5 rectangles on the bottom represent 10 parts chocolate. Now we have the equivalent ratio, 6 to 10. If we look at the ratios as fractions, six-tenths reduces to three-fifths, so we know that they are equal. To review... Ratios describe a relationship between two numbers. They can be represented with the word 'to' or with a colon in standard ratio notation or as fractions. They can also be visually represented with tables and tape diagrams. And remember: with ratios order matters! Looks like Leelee is all ready to give her brownies a taste-test. Hey Leelee! Give a shout-out to all your fans, how did they turn out?