This is a really good mnemonic for remembering the sine and cosine for the five reference angles. ine 30 450 60 90 C aft UJ Thumb Palm of your left hand Flip down the finger that corresponds to the angle whose sine and cosine you need, for instance, 60 There are three digits on the left so the sin 60 0-V3 2 There is one digit to the right so the cos60 -_ V1_1 2 7 Fill out the following chart for the sine and cosine using your left hand. 30 45 60 90 sin 0 VOID / 2 VOIIII / 2 VOIIII / 2 VIIIID / 2 cos e VOID / 2 VOIII / 2 0III/ 2 VOID / 2 VOID / 2