63

The sector is

; there are 360 degrees in a circle.
You use the formula

.
18cm is the radius, and then you square it to get 324.
Multiply 324 by

You get 63
Hello there! :)

It's rational
it's an integer
Hope it helps!
~Just an emotional teen listening to her favorite song "Try Everything"

This system can be a bit tricky unless you write it out:
(2n + 2)(2n - 2) ~ First you have to take one variable and multiply it to each of the other two variables, like:
2n * 2n ~ And:
2n * -2 ~ This gives you:
4n^2 - 4n
Now we do this with the other:
2 * 2n
2 * -2
4n - 4
Now we combine them both while adding like terms:
4n^2 - 4
Therefore your answer is: A. 4n^2 - 4
(This is due to how when having the positive 4n subtracted by the negative it cancels it out. Leaving us with the remaining two terms left.)
I hope this helps, have a great rest of your day! ^ ^
~Ghostgate
The answer to this is Complementary Angles.