The pyramid has a square base and it is symmetrical. That way you only need two numbers to fully describe it, for example length of the base and a height. You are given 4 numbers. If you use pyramid's height 280 feet and the height of its side 356 than they form a right triangle with the base sqrt(356^2-280^2)=219,85 feet. Which should be equal to half the base 440/2=220. That means that you are expected to round feet to the nearest integer. The base is square and its area is 440*440=193600 square feet. Each side is a triangle with height 356 feet and base 440 feet. Area of a triangle is 356*440/2=78320 square feet. Pyramid has 4 equal triangles on its sides and a base. You will need 193600+4*78320=506880 square feet of aluminium to mace the model.