Answer: 
Step-by-step explanation:
The formula that is used to calculate the area of a square is this one:

Where "s" is the side lenght of the square
You know that Julia used 1 foot square stone tiles, then each side lenght of the this tiles is:

Since Julia laid 7 tiles wide by 7 tiles long, the side lenght of the new patio is:

Therefore its area is:
Since Perimeter is Length+ Width, and there are "two lengths" and "two widths", the formula needed here is p=2l+2w. We have the P, so using that, along with knowing that l is 41ft longer than w;
p = 278 , l = w+41
278 = 2l + 2w
278 = 2(w+41) + 2w
We'll use the DISTRIBUTIVE PROPERTY first: 278 = 2w + 82 + 2w
Then we'll COMBINE LIKE TERMS: 278 = 4w + 82
Next we'll subtract 82 from both sides: 196 = 4w
And finally divide both sides by 4:
49 = w
Since the length is w+41 and we now know the width, we can see what the length is: l = w+41 , l = 49 + 41 , l = 90.
Now that we know the length, we can see what the dimensions of the court are:
Perimeter is 278ft
Width is 49ft
And the Length is 90ft.
A=bh {A} stands for the area, {b} stands for the length of your parallelogram, and {h} stands for the height of your parallelogram.
72k² = 9 x 8 x k x k = 3² x 2² x 2 x k x k
so √72k² = √(3² x 2² x 2 x k x k) = √3² x √2² x √2 x √k² = 6k√2
:)