Answer:
s = 130 degrees
Step-by-step explanation:
decagon has a 1,440 degrees interior angles
equation: 1,440 = s + 1310
to find s, add all the known angles
⇒ s + 150 + 170 + 160 + 130 +120 + 160 + 105 + 160 +155
⇒ s + 1,310
equation:
s + 1310 = 1440
subtract each side by 1310
⇒ s + 1310 - 1310 = 1440 - 1310
⇒ s = 130
