triangle issues

sin(81)=10/x so if .9876 = 10/x, what is the length of the hypotenuse.

why is it so small?  do i need to move a decimal?

The reason the hypotenuse is so "small", is because your angle of 81 degrees is so "big". Remember that sin(90)=1 and sin(81)=0.9877, which is very close to 1. So, the side opposite it is going to be almost as long as the side opposite the 90-degree angle, or the hypotenuse!.