Tolong dijawab pake caranya yang jelas, dikumpul besok

s1 = s5 =  95

s2 + s6 = 180
s6 = 180 - s2
s6 = 180 - 110
s6 = 70

s3 + s5 + s6 = 180
s3 + 95 + 70 = 180
s3 + 165 = 180
s3 = 180 - 165
s3 = 15

jadi besar sudut 3 (s3) = 15.