Answer:
x = 61
Explanation:
Formula:
(N {which is the number of sides in the polygon] - 2) * 180 = the sum of all the angles in the polygon.
Simply add the known angles together, subtract that from the above equation and you get the value of x.
(5 {which is N] - 2) * 180
3 * 180 = 540
82 + 121 + 129 + 147 = 479
540 - 479 = x
540 - 479 - 61
x = 61