The fact that this triangle is a right angle triangle makes you now have 2 angles and the 1 side given, so it should be solvable.
First, You know that A=46 and C=90 as it is the right angle, and you know that the sum of any triangle's angles is 180. so now B=180-(90-46)=44
Now to the sides,
sin(B)=opp./hyp.=b/c=8/c=sin(44)
so, c=8/sin(44) which is approximately 11.52 unit length
now, use Pythagoras to find a,
a=√c²-b² =√11.52²-8² which is approximately 8.3 unit length.
Hope this helps.