Calculate the surface area to the nearest tenth of a 13.5 meter cube with a hole 10 meters in diameter drilled through it. Round to nearest square meter.

Question

alekos · Answer

Do you know how to calculate the surface area of the cube without the hole?

anonymous · Answer

Length of edge squared x 6 ? Is that right?

anonymous · Answer

Yes that's right.

Surface area of cube = 6 * area of one edge

Now subtract the area of the hole. Since it is a circle, so take the radius of it (5 meters) and calculate its area. Subtract this area twice from the cube

anonymous · Answer

I can't seem to arrive at any of the choices ? 
A) 1360 m^2  B) 1517 m^2  C) 1674 m ^2  D) 2517 m^2

anonymous · Answer

it seems they have also included the area inner surface of the cylindrical hole

anonymous · Answer

I couldn't get that to work either. I got 1093.5 for SA of cube and  581.19 for SA of cylinder. 1093.5 - 581.19 doesn't give me any of the answers. What am I doing wrong

anonymous · Answer

net surface area = surface area of cube - surface area of two circles + surface area of cylinder without bases

anonymous · Answer

Oh my gosh! Thank you! I didn't think of it like that. I got it now :)