The solution would be like this for this specific problem:
sin(67.5) = sin(135/2)
sin(x/2) = +/- √((1 - cos(x))/√2
sin(67.5) = √(1 - cos(135))/√2 = √(1 + √2/2)/√2 = √(√2/4 + 1/2) = 0.9239
I am hoping that this answer has satisfied your query and it will be able to help you in your endeavor, and if you would like, feel free to ask another question.