Answer: (a) 720°, (b) 120°
Explanation:
A hexagon is a polygon with six sides.
Formula for finding the interior angle of a polygon = ( 2n - 4 )complementary
 = ( 2n - 4 ) 90
 complimentary angle is 90° or
 = ( n - 2 )supplementary
supplementary angle is 180° . Now solving the question now since n = 6
we now put it in any of the formula above
 ( 2 x 6 - 4 ) x 90 = ( 12 - 4 ) x 90
 = 8 x 90 
 = 720° or
 ( 6 - 2 ) x 180 = 4 x 180
 = 720°.
The second part of the question, each size of the interior angle 
 = ⁷²⁰/₆
 = 120°