Answer:

Step-by-step explanation:
Information that we know about the square:
side length:
which can asol be expressed as: 
we can use this information to calculate the area by the formula for the area of a square:

we subtitute the side length:

the square root and the squared exponent cancel each other out (because they are opposite operations) and since this is an area it must have squared units:

The exact value of the area of the square is 
Yes. I completely agree with that person ^^
Use a half-angle identity to find the exact value of sin pi/8