Help ASAP!!!!!A side of the triangle below has been extended to form and exterior angle of 159 degrees.Find the value of s

Answer:
x=21
Step-by-step explanation:
45+x+the last angle=180
x+159=180
180-159=21
21+45= 66
180-66=114
so i think x would be 21 degrees but im not entirely sure do not quote me on this sorry