Chapter 7 - Similarity - 7-1 Ratios and Proportions - Practice and Problem-Solving Exercises - Page 437: 32

$\frac{b}{a}$=$\frac{4}{3}$; First Property of Proportions

The First Property of Proportions states $\frac{a}{b}$=$\frac{c}{d}$ is equivalent to $\frac{b}{a}$=$\frac{d}{c}$ You are given $\frac{a}{b}$=$\frac{3}{4}$ Therefore $\frac{b}{a}$=$\frac{4}{3}$