Solution
In a cyclic quadrilateral, opposite angles is supplementary.
=> 3x - 59 + 2x - 1 = 180
=> 5x - 60 = 180
=> 5x = 180 + 60
=> 5x = 240
=> x = 48
Angle A = 2(48) + 4 = 100
Also, A + C = 180
=> C = 180 - 100
=> C = 80
