please answer this question!

The length and width of a cardboard are 22 ft and 10 ft. We are going to cut out the corners and fold up the sides to form a box. Determine the height of the box that will give maximum volume Note: Write only the numerical value of the height, the units are already written. Write the exact answer not the decimal approximation (for example write 3+15 then write 3+15 not 0.8). Also, if the answer is or (3+sqrt(5))/4 4 4 Answer. The height of the box that will give maximum volume is