Let’s find the area of the triangle first, the height is 10 and the base is 5, with this we can use the formula 1/2bh=A. 1/2(5)(10)= 25 there are 4 triangles and they are all the same, so with just the triangles we get 25*4=100, now we need the bottom, it’s only a square, and squares have the same length on every side, we only need to multiply 5*5 and then add it to the area we got from the triangles (100). So 5*5, 25, 100+25, 125. The surface area of the pyramid is 125 in ^2