Well, if you use the net diagram, the one below the pyramid, this is how to do it: First, find the area of the square, or the base. That would be 10 * 10 = 100ft. Then, you find the areas of all of the triangles, which is this formula: A= BH / 2. So you would do 10 * 12 / 2 for each triangle, or you can just make them squares, since there are four triangles, and it would turn into 10 * 12 * 2 for all of them. That was just an easier way to figure it out, but you could have done each triangle and then added them all up. Finally, add what you get for the triangles, 240ft, with the area of the square, 100ft. You get 340ft². Your answer will be 340ft². Hope this helped!
