try 5.5 or 5 1/2 I hope this helps!
With Sine, Cosine, and Tangent there are no limits with the numbers you can use and they can be found on a calculator. When you press one of the 3 it will show up like:
Sine(
Cos(
Tan(
Than just add your number and press enter
60+90=150 no it does not make a supplementary angle.
False it would be equal to 15+3x