Jawabanmu

2014-03-03T14:11:18+07:00
30 = cos 0 = 1
60 = cos 30 = √3/2
90 = cos 60 = 1/2
120 = cos 90 = 0
150 = cos 120 = -1/2
180 = cos 150 = -√3/2
210 = cos180 = -1

mohon maaf bila ada salah,,di cek dulu ya