Answer
3.4
Work Step by Step
Recall the following rule: $\frac{a}{b} \div \frac{c}{d}=\frac{a}{b} \times \frac{d}{c}$.
We convert the decimal into a fraction for the ease of simplification:
$7.14\div2.1$
=$\frac{714}{100}\div\frac{21}{10}$
=$\frac{714}{100}\times\frac{10}{21}$
=$\frac{714}{10}\times\frac{1}{21}$
=$\frac{102}{10}\times\frac{1}{3}$
=$\frac{34}{10}\times\frac{1}{1}$
=$3.4$