Answer:
Erm. If you know pie use it with the 3.141 Since its a half circle i believe you need that since thats the equasion with it. I don't really know :P
Step-by-step explanation:
this could take a while to think about but uhh i dont know,
15a^6 + 15a²b
that would be just multipacation
Answer: 63
X = 63
Its adjacent meaning they will add up to 180 degrees