## Basic College Mathematics (10th Edition)

$\frac{x}{20} = \frac{6.5}{0.4}$ We need to find the unknown Number in the proportion. First we will multiply the right side of the proportion by 10 in both numerator and denominator. i.e. $\frac{x}{20} = \frac{6.5\times10}{0.4\times10} = \frac{65}{4}$ Now, we need to find the cross product i.e. $x\times 4 = 65 \times 20$ So, $4 x = 1300$ Divide both sides by 4 i.e. $4 x \div 4 = 1300 \div 4$ so, $x = 325$