How many sides does a polygon have if the sum of its interior angles is 1,260º?

If a polygon have the sum of its interior angles is 1,260 it has to be 5 sides

one angle = 360 / n

Let x be the angle and n be the number of sides.

x = 360 / n

nx = 360

now, let's use this:

(2n - 4) * 90 = 1260

2n - 4 = 1260 / 90

2n - 4 = 42 / 3

2n - 4 = 14

2n = 18

n = 9

x = 360 / 9

x = 40 degrees for each exterior angle

so the interior angle's measurement is 140 degrees

So 9 would be the answer