Find the missing number in the box:
$$\dfrac{3}{5}=\dfrac{\square}{20}$$
Ratios that are equal are called equivalent ratios and are said to be in proportion. To find an equivalent ratio, we multiply or divide both the numerator and denominator by a same number. $$\dfrac{3}{5}=\dfrac{\square}{20}$$
$$5$$ is multiplied by $$4$$ to get $$20$$, So we multiply numerator, 3 as well by $$4$$
$$\dfrac{3}{5}=\dfrac{12}{20}$$
$$\therefore \textbf{The missing number is 12}$$