Answer:
its B
Step-by-step explanation:
Get on mathpapa is shows you the answer and how to explain it
Answer:
45 
Step-by-step explanation:
Multiply 9 · 10 = 90 then divided by 2 = 45
Yes, they can add up to 180 degrees. Say one angle is 65 degrees, and the other one is 115 degrees. That would equal to 180 degrees.
Hope this helps.