1. Lesson 69:
*constant of proportionality – the number that relates 2
variables in a direct variation
*direct variation – a proportional relationship between 2
variables in which one variable is a constant multiple of the
other, that is, the quotient of the 2 variables is a constant
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2. *dependent variable - the variable in an equation whose value is
determined by the value chosen for one or more of the other
variables
*independent variable - a variable in an equation whose value
can be freely chosen
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3. How to tell if a function is an example of direct variation:
--the graph intersects the origin
--the function is linear (forms a line)
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4. Lesson 69 Examples:
pg. 467
A) p = 3s
c. of p. = 3
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5. B) No - not proportional
Not direct variation - Sergio's age isn't a constant multiple of
Fernando's.
C) 20 gallons 30 gallons C. of P. =
166 pounds X 166 pounds
20 gallons
p = 8.3g
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