I keep getting this flagged as wrong, but I'm not sure why

> 
> Find $\sec\theta$ and $\tan\theta$ if $\sin\theta = -3/4$ and in Quadrant 4.
> 
> 
> 

My result was: 

$\sec\theta = -4\sqrt7/7$

$\tan\theta = 3\sqrt7/7$

What am I missing?