The measurements from my box are W-28cm L-17.4cm H2.4cm. I have to find the surface area of the box, as well as the volume.For the volume, I have the formula 1/2 base*height*width, so would that be 1/2 * 17.4 * 2.8 * 2.4, or do i find the area of the triangle, and then multiply by the height? For the surface area, would i find the area of the rectangle( 17.4 * 2.8) and then multiply by three for the three rectangles, and then find the area of the end triangle, and multiply by 2? Im just a little confused.Thanks!