Direct Variation

Find the constant of variation (k)

100

y=3x What is k?

3

200

y=x/2 What is k?

1/2

300

In what year did Columbus sail the ocean blue?

What is 1492?

400

y=100 x=5 What is k?

20

500

y=1/3 x=1/2 What is k?

2/3

Write equation given y and x

100

y=6 and x=3. Write the direct variation equation.

y=2x

200

What is Mr. Jones favorite color?

Green

300

y=256 and x=4. Write the direct variation equation.

y=64x

400

y=500 and x=25. Write the direct variation equation.

y=20x

500

y=1/4 and x=1/8. Write the direct variation equation.

y=2x

find x or y

100

If y=2x and x=4, what is y?

8

200

If y=.3x and x=10, what is y?

3

300

If the point (2,1) is part of a direct variation graph find x if y is 10

What is 20?

400

If y=.5x and y=6, what is x?

12

500

If (3,2) represents a direct variation, find the missing value (6,x)

4

Proportional vs Non Proportional

100

What state is Mr. Jones from?

Louisiana

200

Is the following a direct variation function? y=(1/2)x

yes

300

Is the following a direct variation function? y=x+2

no

400

Is the following a direct variation function? y=2x-3

no

500

y=x/3

yes

Questions/Definitions

100

What is the y-intercept of a direct variation function?

What is 0?

200

Which is the only planet to spin clockwise?

Venus

300

What is the constant of a proportionality variable? (which variable)

k

400

In a direct variation function, which variable is the dependent variable?

y

500

What number/value can k not equal/have?

0