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Algebra Lesson 4-6 Worksheet
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Tell whether the equation represents direct variation. If so, identify the constant of variation.
1.) y  8 x
2.) y  2 x  1
3.) 3x  y  6
Graph the direct variation equation.
6.) y 
5.) y  2 x
4.) 8 y  6 x
3
x
4
The graph of a direct variation equation is shown.
a.) Write the direct variation equation.
b.) Find the value of y when x = 10.
7.)
8.)
a.) ______________________________
a.) _______________________________
b.)
b.)
Tell whether the table represents direct variation. If so, write the direct variation equation.
9.)
x
3
5
7
9
y 12 20 28 36
10.)
x 50 40 30 20
y
5
4
3
2
Given that y varies directly with x, use the specified values to write a direct variation equation that
relates x and y.
11.) x = 24, y = 3
12.) x = 5, y = –30
13.) The amount w of water (in gallons) used by a shower head varies directly with the number m of minutes
the shower is run. For a 3 minute shower, 7.5 gallons of water is used.
a) Write a direct variation equation that relates w and m.
b) How many gallons of water do you use if you take an 8-minute shower?
14.) One way to keep moisture out of your basement is to paint the walls with a waterproof paint.
The number g (of gallons) of paint you need varies directly with the area A of the basement.
Two gallons of paint covers 200 square feet.
a) Write a direct variation equation that relates g and A.
b) How many gallons do you need to cover 530 square feet?
c) How many square feet does 8.5 gallons of paint cover?
15.) The table shows the amount of time t (in seconds) it takes to download a file of size s (in kilobytes).
a) Explain why s varies directly with t.
b) Write a direct variation equation that relates s and t.
c) How long will it take to download an 800-kilobyte file?
Time, t (sec)
15
File size, s (kb)
420
30
45
840
1260
(Round your answer to the nearest second.)