Answer:
see explanation
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 = 6 ( sides of a hexagon ) , then
sum = 180° × 4 = 720°
(a)
let x be the sixth interior angle , then
90° + 100° + 110° + 120° + 130° + x = 720 , that is
550° + x = 720° ( subtract 550° from both sides )
x = 170°
(b)
the sum of the exterior angles of a polygon is 360°
exterior angle + interior angle = 180°
exterior angle = 180° - interior angle
Then
180° - 90° = 90°
180° - 100° = 80°
180° - 110° = 70°
180° - 120° = 60°
180° - 130° = 50°
180° - 170° = 10°
sum = 90° + 80° + 70° + 60° + 50° + 10° = 360° ← correct total
