First, find the area of all figures that make up the net. The formula for the area of a triangle is 1/2bh, and there are four triangles. Therefore, 4(1/2)(10ft)(12ft)=240ft^2. This is the area of the outer four triangles of the pyramid. You then add this to the area of the square in the middle (s^2)=(10^2)=100ft^2, so it would be 100ft^2+240ft^2=340ft^2.
