Cos O.86 dan 0,77 berapa radian ? Mohon dijawab

satuan sudut  radian
π rad = 180°

cos x = 0,866  = 1/2 √3 = cos 30
cos x = cos (30/180)π rad
cos x = cos (1/6) π rad


cos  x  = 0,777 = 1/2 √2 = cos 45
cos x = cos (45/180) πrad
cos x = cos (1/4) π rad