Answer:
314 mile²
Step-by-step explanation:
area = πr² = 3.14 x 10² = 314 mile²
The height of this triangle would be 10.4
In order to find this, you first must find the length of the sides. Using a manipulated formula for area of an equilateral triangle, we can determine the lengths of the side. Below if the formula.
S = 
In this, S is the length of the side and A is the area. So we plug in and get:
S =
S = 
S = 12
Now that we have the side as 12, we can use the Pythagorean Theorem to find the height. If you split a equilateral triangle down the middle, you are left with two right triangles. Using this right triangle, the hypotenuse would be 12, the first leg would be 6 (half of the base) and the height would be the other leg. So we plug in and solve.




h = 10.4
$736 because $184 x 4 would give you your amount.
I am assuming you wrote the problem wrong. Is it a^2?
A^2 -4A-21=0
(A-7)(A+3)=0
A=7 A=-3, ignore the negative number because it doesn't make sense if you plug in for a.
length=a+3=7+3=10
Width=7=a