#7
1. Find the volume of the pyramid (l×w×h/3); you should get 64cm³
2. Find the volume of the cube (l×w×h); you should get 512cm³
3. Add the two products; the glass paperweight's volume is 576cm³
#8
1. Find the surface area (SA) of the cube (area of one square×5); it is 320cm²
2. Find the SA of the pyramid (exclude the square base); it is 80cm² ((slant height×(length/2))×4)
3. Add the surface areas; the sum should be 400cm²