Question

The interior angles of a polygon are in

a.P. If the least angle is 42 and common difference is 33, the number of sides is

Answer 1

[2a+(n-1)d](n/2) = 180(n-2)
84+(n-1)33 = 360 (n-2)/n
51 + 33n = [360n -720]/n
51n + 33n^2 = 360n - 720
33n^2 - 309n + 720 = 0
n=4