Answer
117
Work Step by Step
Solving Variation Problems (see p. 424)
1. Write an equation that models the given English statement.
2. Substitute the given pair of values into the equation in step 1 and find the value of k, the constant ofvariation.
3. Substitute the value of k into the equation in step 1.
4. Use the equation from step 3 to answer the problem's question.
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1.
$y$ varies directly as $x$, or $y$ is directly proportional to $x$.
$y=kx$
2.
$45=k(5) \qquad /\div 5$
$k=9$
3.
$y=9x$
4.
$y=9(13)=117$