Question 990236
one of the angles will be 80 degrees.
the other angle will be 160 degrees.
the sum of the angles of the nonagon will be equal to 1020 + 240 = 1260.


a nonagon has 9 sides.
the sum of the angles of the nonagon are equal to (9-2)*180 = 7 * 180 = 1260.
the sum of the angles of a nonagon is also equal to 9 * (180 - 360 / 9) which is equal to 9 * 140 which is equal to 1260.
both formulas lead to the same sum of angle of a nonagon (nine sided figure).
once you know that, it's a simple formula to derive the angles.
let one of the angle = x and the other angle = 2x.
their sum is 3x.
1020 + 3x = 1260
3x = 1260 - 1020
3x = 240
x = 80.
2x = 160.