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TUESDAY, DECEMBER 6TH
Please take out homework
(Worksheet) and complete
warm up
Did you write down the
homework?
o
o
1.
Find k in each proportion
y=5x
2. y=2/3x
DID ANYONE TRY THIS?
For most people, the ratio of the
length of their head to their total
height is 1:7. Use proportions to test
your measurements and see if they
match this ratio.
CORNY JOKE
OF THE
DAY
What do you call
a cow who can’t
give milk?
An “udder”
failure!
WHERE IS THE ORIGIN?!?!
IS THIS AN EXAMPLE OF DIRECT VARIATION?!
1/6 is not the same as 2/8 or 3/10 or ……….
X
y
1
6
2
8
3
10
4
12
5
14
HOMEWORK ANSWERS
Step 1: Is it a direction
Variation?
Make a graph that shows the
relationship between the number
of minutes and the distance the
train travels.
Plot the points.
The points lie in a
straight line.
(0, 0) is included.
Determine whether the data set shows direct
variation by finding the proportions AND
graphing it!
Kyle's Basketball Shots
Distance (ft)
Number of Baskets
Proportion Check:
20
30
40
5
3
0
You can also compare ratios to see if a direct variation occurs.
60
5 ? 3
20 = 30
150  60.
The ratios are not proportional.
150
The relationship of the data is not a direct variation.
Graphing Check:
Number of Baskets
5
4
3
2
1
20
30 40
Distance (ft)
y is 54 when x is 6
y = kx
54 = k  6
y varies directly with x.
Substitute for x and y.
9=k
Solve for k.
y = 9x
Substitute 9 for k in the original equation.
x is 12 when y is 15
y = kx
y varies directly with x.
15 = k  12
Substitute for x and y.
5=k
4
5
y= x
4
Solve for k.
5
Substitute for k in the original equation.
4
y is 8 when x is 5
y = kx
y varies directly with x.
8=k5
Substitute for x and y.
8=k
5
Solve for k.
8
y= x
5
Substitute8 for k in the original equation.
5
•
The table shows the amount of money Max makes for different
amounts of time he works.
•
Determine whether there is a direct variation between the two
sets of data.
•
If so, find the equation of direct variation.
•
Graph the variation (Make sure to label each side)
direct variation; y = 12x