## Elementary Technical Mathematics

Divide $6\frac{2}{3}$ by $1\frac{3}{4}$ to obtain: $=6\frac{2}{3} \div 1\frac{3}{4} \\=\frac{3(6)+2}{3} \div \frac{4(1)+3}{4} \\=\frac{20}{3} \div \frac{7}{4}$ Use the rule $\frac{a}{b} \div \frac{c}{d} = \frac{[a}{b} \times \frac{d}{c}$ to obtain: $\\=\frac{20}{3} \times \frac{4}{7} \\=\frac{20(4)}{3(7)} \\=\frac{80}{21} \\=3\frac{17}{21}$ Thus, 3 pieces of pipes $1\frac{3}{4}$ ft long can be obtained from the original pipe.