8.5 yd/1 * 3ft/1yd ................
By definition, we have

So, we have to solve two different equations, depending of the possible range for the variable. We have to remember about these ranges when we decide to accept or discard the solutions:
Suppose that 
In this case, the absolute value doesn't do anything: the equation is

We are supposing
, so we can accept this solution.
Now, suppose that
. Now the sign of the expression is flipped by the absolute value, and the equation becomes

Again, the solution is coherent with the assumption, so we can accept this value as well.
hope this helped is not sorry
Good idea to look up the formula for "surface area of a sphere" and to write it down for later reference. It is A=4 pi r^2, where r is the radius of the sphere.
If the given sphere has a diameter of 7 cm, what is the radius of this sphere?
Write your answer inside the parentheses, below:
Sphere surface area = 4 pi (r)^2, or (in this case), A = 4(3.14)( )^2
The answer is 4 square root 5 or -4 square root 5