Answer:

Step-by-step explanation:

Answer:
It is an octogan and it isn't regular, you are correct.
Step-by-step explanation:
Normal octagons look like a stop sign. This one looks like a star.
Answer:
0
Step-by-step explanation:
-10 + 10
-10 and 10 are additive inverses, so when we add them, it is equal to zero
-10 + 10 = 0
The answer to number one is 18 and the answer to number two is -1
Go to where 30 degrees is on the unit circle and find the y-coordinate. That is sin30.