What is \pi x^{2}?with this question! thx

Understanding your post takes a bit of guesswork.  I'm assuming you mean the following expression:

pi * r^2      ("pi times the square of the radius, r").

Unless you share the value of "x," we can't go any further.  The intermediate answer is 

pi * x^2.

If x represented the radius of a circle, and if x=3 inches, then the area of the circle would be

A = pi * (3 inches)^2, or p * 9, or 9 * pi.

Or you could approximate pi with "3.14":  Area = A = 3.14 * 9.  Evaluate this to 2 decimal places.

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3.00 off usually comes before tax =31.41
sales tax is 5.32 = 36.73