# How do you determine whether the two ratios form a proportion: 6/9, 10/15?

Nov 18, 2016

The ratios are equal and form a proportion.

#### Explanation:

To find out if $6 : 9 = 10 : 15$

$\frac{6}{9} \mathmr{and} \frac{10}{15} \text{ } \leftarrow$ cross- multiply

$6 \times 15 = 9 \times 10$

$90 = 90$

Therefore the ratios are equal and form a proportion.
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OR
Change each ratio to its simplest form:

$\frac{6 \div 3}{9 \div 3} \mathmr{and} \frac{10 \div 5}{15 \div 5}$

$\frac{2}{3} = \frac{2}{3}$