Need some help with trigonometry related questions

[haxxiy]

Man, you just reminded me how much I hate mathematics. The only thing I remember about trigonometry is that:

Cos 90 = Sin 0 = srt 0 / 2

Cos 60 = Sin 30 = srt 1 / 2

Cos 45 = Sin 45 = srt 2 / 2

Cos 30 = Sin 60 = srt 3/ 2

Cos 0 = Sin 90 = srt 4 / 2

Kinda easy way to memorize it, eh?