Direct Variation

Direct Variation

What is direct variation?

• Direct variation describes a simple relationship between two variables . We say y varies directly with x (or as x , in some textbooks) if: y=kx. for some constant k , called the constant of variation or constant of proportionality 

Examples of Direct Variation

• The number of hours you work DIRECTLY impacts the amount of money you make

• The amount of weight on a spring DIRECTLY impacts the distance the spring will stretch

• The speed of a car DIRECTLY impacts the distance traveled in a certain amount of time.

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y varies directly with x.  When y=3, x=9.  Find x when y=12.  

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y varies directly as x. When y=10, x=2. Find y when x=13.

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The weight of an object on Earth varies directly as the weight of the same object on the moon. A 300 pound object would weigh 48 pounds on the moon. How much would a 65 pound object weigh on the moon?

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The amount of money raised at a charity fundraiser is directly proportional to the number of attendees. The amount of money raised for five attendees was $100. How much money will be raised for 60 attendees?

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Fill in the missing value on the table