Intro to Direct Variation

 y varies directly with x, and y is 84 when x is 16. What is the constant of proportionality?

• y = (21/4)x
• k= 21
• k= 5.25
• k= 4/21

Write an equation for this relationship.

• y=4x
• y=1/8x
• y=1/4x
• y=8x

The amount of money earned on a job is directly proportional to the number of hours worked.  If $70.00 is earned in 5 hours, how much money is earned in 22 hours of work?

• $2
• $308
• $1.57
• $265

Is the given table a direct variation? If so, what is the constant?

• Yes; 1/4
• Yes; 4
• Yes; 2
• No

In a direct variation, y=39 when x=3.  Find the value of y when x=2.

• 26
• 3
• 58.5
• 2

Is this a direct variation?
y=2x

• yes
• no

Does the relationship represent direct variation?

• Yes
• No

Write the equation for the table given.

• y = 1/3x
• y = 3x
• y = 1/2x
• y = 2/3x

Is this table proportional?

• Yes
• No

Which equation is NOT an example of direct variation?

• y = 2x + 4
• y = x
• y = -x
• y = 1/2x