Answer
$\sin -270^{\circ}=1$
Work Step by Step
1. What we know about -270 degree angle
$\theta=90^{\circ}$ (because it is a co-terminal angle and values of x and y will be the same)
$x=0$
$y=1$
$r=1$
2. Substitute in:
$\sin\theta=\frac{y}{r}=\frac{1}{1}=1$
