Question

Can someone help me with my homework? (S=730 in^2 is incorrect)

Answer 1

The composite shape consists of a cube and a cuboid.

Once face of the cube has been fused with the cuboid, so we will consider only 5 faces of the cube. And also subtract the area of one face of the cube from the cuboid

So total surface area of the composite shape becomes

`\begin{gathered} 5l^2+2(lw+lh+wh)-area\text{ of one face of cube} \\ 5*4^2+2(15*10+15*7+10*7)-4^2 \\ 80+2(150+105+70)-16 \\ 80+2(325)-16 \\ 80+650-16 \\ 714in^2 \end{gathered}`

Hence the first option is the answer