What is the sum of angles in a octadecagon?
( n x 180 ) - 360
n is the number of sides.
In other words,
take the number of sides or your polygon and multiply that by 180.
then, subtract 360 from that result.
that is your answer.
An octadecagon has 18 sides.
( 18 x 180 ) - 360 = 2880
The sum of the interior angles of an octadecagon is 2880 degrees.
Supplementary angles has the sum of the two angles that equal 180 degrees, while complementary angles have the sum of 90 degrees between two angles. Complementary angles sum to 90º, like 30º + 60º. Supplementary angles sum to 180º, like 45º and 135º. SUPPLEMENTARY ANGLES = the sum of the two angles are 180 WHILE COMPLEMENTARY ANGLES= the sum of the two angles are 90
If we are talking about the sum of the interior angles, the sum is (11-2)x180 degrees. This is 180x9 or 1620 degrees. The sum of the exterior angles is always 360 so that is why i assumed we were talking about the interior angles. Given a polygon with n sides, the sum of the interior angles is (n-2)x180 degrees.