This equation is killing me, Sin(2T) = (625/4) x sin(40)

I have need to solve it for T where T is the angle. However I either end up getting an error or an angle that is less than 1 degree which i know is wrong.

Initially i tried doing the 625/4 x sin 40 which gave me 100.44

So i had Sin(2T) = 100.4

then tried to take the Sin of both sides but get an error on my calculator.

Please help me, it seems so simple to me but i just cant get my brain to work