First find the sum of the interior angles in this polygon by using the formula (n - 2) × 180, where n is the number of sides.
There are 7 sides in this polygon, so plug 7 in for n.
(7 - 2) × 180
5 × 180 = 900
The sum of the interior angles in this 7-gon is 900°. Now to find x, you will need to add up all the other angles and subtract your answer from 900.
900 - (∠A + ∠B + ∠C + ∠D + ∠E + ∠F) ⇒ 900 - (146 + 122 + 142 + 140 + 110 + 142) = 98
x = 98°
