Answer:
52 sides
Explanation:
The only way I know how to do this is to create one fraction which is a combination of 2 steps used when 1 of the interior angles is known.
Formula
360/(180 - 9000/s ) = s
Multiply denominator and numerator on the left by s.
360 * s
======= = s
s* (180 - 9000/s)
Remove the brackets on the denominator
360s
================ =s
180s - 9000
Cancel the numerators s's.
360 / (180s - 9000) = 1
Multiply both sides by 180s - 9000
360 =180s - 9000
Add 9000 to both sides
360 + 9000 = 180s
9360 = 180s
Divide by 180
9360/180 = 180/180 s
s = 52