I believe that Cphill already posted an answer for this question (for another question). This is what he said:
"Sum of the interior angles of a polygon = (n - 2) (180) where n is the number of sides
So we have this
(n -2) (180) = 160 + 146 (n - 1) simplify
180 n - 360 = 160 + 146n - 146
180n - 360 = 14 + 146n
180n - 146n = 360 + 14
34n = 374
n = 374 / 34 = 11 sides"
