Chapter 1 - Review Exercises - Page 44: 27

$\sin180^{\circ}=\frac{y}{r}=\frac{-4}{5}=-\frac{4}{5}$ $\cos180^{\circ}=\frac{x}{r}=\frac{3}{5}$ $\csc180^{\circ}=\frac{r}{y}=\frac{5}{-4}=-\frac{5}{4}$ $\sec180^{\circ}=\frac{r}{x}=\frac{5}{3}$ $\tan180^{\circ}=\frac{y}{x}=\frac{-4}{3}$ $\cot180^{\circ}=\frac{x}{y}=\frac{3}{-4}=-\frac{3}{4}$

x=3; y=-4 $r=\sqrt {x^{2}+y^{2}}=\sqrt {(3)^{2}+(-4)^{2}}=\sqrt {25}=5$