Question

AB & BC are two sides of a regular octagon. Calculate the size of angle x. ​

Answer 1

x = 45°

Explanation:

the sum of the interior angles of a polygon is

sum = 180° (n - 2) ← n is the number of sides

here n = 8 ( number of sides of an octagon ) , then

sum = 180° × 6 = 1080°

the interior angles of a regular octagon are congruent , so

∠ ABC = 1080° ÷ 8 = 135°

x and 135° are adjacent angles on a straight line and sum to 180° , then

x = 180° - 135° = 45°