Answer:
x = 100°
Step-by-step explanation:
The sum of the interior angles of a polygon is
sum = 180° (n - 2) ← n is the number of sides
here n = 7, hence
sum = 180° × 5 = 900°
Sum the given interior angles and equate to 900
x + 155 + 116 + 135 + 135 + 116 + 143 = 900
x + 800 = 900 ( subtract 800 from both sides )
x = 100°
