I have solved a few math problems for my webwork homework, yet when I enter them into the website it tells me my answers are wrong and I am becoming quite frustrated, can anybody help me?

Ex:

If 1100 square centimeters of material is available to make a box with a square base and an open top, find the largest possible volume of the box.

my answer: 3263 or 3262, depending on how you round it up:(both entered in as attempts, both wrong)

Ex2: A Norman window has the shape of a semicircle atop a rectangle so that the diameter of the semicircle is equal to the width of the rectangle. What is the area of the largest possible Norman window with a perimeter of 46 feet?

(pi x r) + 6r

Now, set that equal to 46 feet and solve for r (factor it out in the equation)

r(pi + 6) = 46

9.14 r = 46

r = (around) 5.03 feet

Now, the AREA of that window is half the area of a circle of radius r, PLUS the area of the supporting rectangle, or the length of the sides (2r) squared.

1/2 (pi x r^2) + 10.06^2

my answer: 141 square feet(wrong)