Solving a Proportion by

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Solving a Proportion by Cross Multiplying
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A Ratio and a Proportion
Ratio The relationship in quantity, amount, or
size between two or more things. Typically
expressed as a quotient of two mathematical
expressions (i.e. A FRACTION). For example
Proportion An equation that equates two ratios
(i.e. TWO EQUAL FRACTIONS). For example
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Solving a Proportion

• Solve

Solve
Cancel the divide by X
Cancel the divide by 5
Cancel the divide by 3
Cancel the divide by 2
4
Solving a Proportion

• Solve

Solve
Notice the pattern will eliminate a lot of work.
Multiply opposite numerators and denominators.
The products are EQUAL.
Cross Multiplication can be used to solve a
proportion.
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Solving a Proportion

• Solve

Solve
Multiply each numerator by the opposite
denominator and set the products equal to each
other.