Ratio Tables

Today's Goal: Today students will be able to create ratios tables of equivalent rations using scaling.

We call these ratio tables as the table has columns having pairs of numbers with the same ratio. Here is an example ratio table:

In this table we see that in week #1 $3 were saved. In week #2 and total of $6 has been saved. IN the third eek a total of $9 had been saved. 1:3, 2:3, and 3:9 are equivalent ratios. They have the same relationship. This can be checked by reducing them to simplest form. You will see if we reduce 2:6 by dividing each number by 2 the result is 1:3. If we reduce 3:9 by dividing both number by 3 we again see the result is 1:3.

Here is an example to work through together.

Videos

The number we are looking for is the bottom number of the ratio where the distance is 15 miles. Our task is to create an equivalent ration in the middle column and in the last column. If we do this we will know how long it will take an ostrich to run 15 miles.

First question is, what can I do to the 50 to get it to be a factor if 15. I could divide by 2 but the quotient 25 is not a factor of 15. I can divide by 10. The quotient 5 is a factor if 15 so let's do that.

Practice Sites

IXL: - Limited practice - complete the table by filling in the missing values.

Finish the Table - Another activity where you provide the missing values to the table.

Math Games - Limited Practice (5 problems) Complete the ratio table.

Then whatever I do to one number, I have to do the same thing to the other number in that ratio. So, let's divide the time by 10.

Now I see that if I multiply 5 by 3 I get the 15 I want in the Distance row and last column. So I multiply 5 by 3 and get 15

Again, whatever I do tone number of the ratio, I have to do the same thing to the other, so let's multiply 6 by 3.

When I do this, I see that the Time that goes with the 15 miles is 18. So, I have learned that an ostrich can run 15 miles in 18 minutes.

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