how to solve 16sin36/sin72
Notice that we can write
16 sin36 / sin(36 + 36) =
16 sin 36 / (sin36cos36 + sin36cos36) =
16 (sin 36) / [(sin36) [cos 36 + cos36] =
16 / (2 cos 36) =
8/cos 36 = 8(1/cos36) =
8sec36 = about 9.89
