Answer:
x = 252
Step-by-step explanation:
the sum of exterior angles of a shape with n sides is (n – 2)180.
n is just used when we don't know how many sides it have, in this case its 5
(5 – 2)180
(3)180 = 540
to 540 is the sum of all the exterior angles
60 + 51 + 108 + 57 + (x + 12) = 540 now solve for x
276 + (x + 12) = 540
288 + x = 540
-288 -288
x = 252
