Answer
$y\approx21.92$
Work Step by Step
$A=55^{\circ},s=21,r=22$
$s=r\cdot C$
$21=22C$
$C=\frac{21}{22} radian$
$C=54.695^{\circ}$
By laws of sines,
$\frac{r}{sinA}=\frac{y}{sinC}$
$\frac{22}{sin55^{\circ}}=\frac{y}{sin54.695^{\circ}}$
$y\approx21.92$