In triangle ABC, the angles A, B, C form an arithmetic sequence. if A = 17 degrees, then what is angle C, in degrees?
A + B + C = 180
17 + (17 + d) + (17 + 2d) = 180
51 + 3d = 180
3d = 180 - 51
3d = 129
d = 129 / 3 = 43
C = 17 + 2(43) = 103°
