Answer:
x = 97
Explanation:
the sum of the interior angles of a polygon is calculated as
sum = 180° ( n - 2 ) ← n is the number of sides
here n = 6 , then
sum = 180° × (6 - 2) = 180° × 4 = 720°
sum the 6 angles, equate to 720 and solve for x
98 + 155 + x + 10 + 120 + 140 + 100 = 720 ( simplify left side )
x + 623 = 720 ( subtract 623 from both sides )
x = 97