1. Unit 7 - Lesson 4 Direct Variation
Learning Goals:
I can determine if a linear relation shows Direct Variation
I can create a rule for a linear relation
and use it to solve questions. 13

2. Unit 7 - Lesson 4 Direct Variation
Warm Up
Determine the Rate of Change
for the following graph.
Find to two points on the line.
Calculate the 𝐶ℎ𝑎𝑛𝑔𝑒 𝑖𝑛 𝑅𝑖𝑠𝑒 𝐶ℎ𝑎𝑛𝑔𝑒 𝑖𝑛 𝑅𝑢𝑛
What does the Rate of Change mean in this example?

3. Unit 7 - Lesson 4 Direct Variation
Warm Up
Can we use the Rate of Change
to create a rule?
How much money will be in your
Savings Account after
two and half years? (use the rule)

4. Unit 7 - Lesson 4 Direct Variation
Warm Up
How much money was in the
Savings Account just before
we began?
How long would it take to earn $950? (Interpolate or Extrapolate?)
How much money will you have in
your Savings Account after 11.5 months? (Interpolate or Extrapolate?)

5. Unit 7 - Lesson 4 Direct Variation
Have a look at the data in this table. Is this a linear relation?
Notice that when we
double the values in
one column...
… they double
in the other column.
We can say that the Canadian Dollar is
Directly Proportional to the New Zealand Dollar.

6. Unit 7 - Lesson 4 Direct Variation
The following data was collected from Centre in the Square
Let’s find the First Differences! What does it mean?
Can we create a rule for this relation?
Lets use the rule to determine the cost of 20 tickets.

7. Unit 7 - Lesson 4 Direct Variation
The following data was collected from Centre in the Square
Is the number of tickets you purchase Directly Proportional to the cost?
- Can you double the values in one line to get the values in another?
Does the data pass through the origin (0,0)?
Does the data show a linear relation?

8. Unit 7 - Lesson 4 Direct Variation
Which of the following graphs show Direct Variation?
What does this squiggle mean?
- Can you double the values at one point to get the values in another?
Does the data pass through the origin (0,0)?
Does the data show a linear relation?

9. Unit 7 - Lesson 4 Direct Variation
Which of the following graphs show Direct Variation?
- Can you double the values at one point to get the values in another?
Does the data pass through the origin (0,0)?
Does the data show a linear relation?

10. Unit 7 - Lesson 4 Direct Variation
Learning Goals:
I can determine if a linear relation shows Direct Variation
I can create a rule for a linear relation
and use it to solve questions.
Homework
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