Answer: 
Step-by-step explanation:
For this exercise it is important to remember that, by definition, the length of the minor arc can be calculated wih the following formula:

In this case , according to the data given in the exercise, you know that:

Therefore, susbtituting those values into the formula, you get that length of AB is the following:

Answer:
I think the right answer is A
sorry if I am wrong
X(-x^4)(-x^4)=
The answer is x^9
Do 40x10=400. Then do 40x6=240. Lastly, add 400+240=640.