Thread: Pyramid Problem

The regular pyramid roof of the Washington Monument is 55 ft. high and has a base which is a square 35 ft. 2 in. on a side. The marble slabs of which it is built weigh 165 lb. per cu. ft. If the room covered by the roof is a pyramid whose square base is 34 ft. on a side and 54 ft. high, what is the weight of the roof? (Neglect the six small windows.)

Start by calculating the volume. The bigger pyramid minus the smaller one (room/empty space)

Originally Posted by Solarmew

Start by calculating the volume. The bigger pyramid minus the smaller one (room/empty space)

I'm confuse. Can you explain it more? What will I do in the weight of the marble?

you have to find the volume of the roof, so you take the outside limits, which are defined by the hight of 55' and a square base with a side of 35' 2" and the inside limits (because the room itself is empty and does not add to the weight, so you subtract its volume from the total)

Originally Posted by Solarmew

you have to find the volume of the roof, so you take the outside limits, which are defined by the hight of 55' and a square base with a side of 35' 2" and the inside limits (because the room itself is empty and does not add to the weight, so you subtract its volume from the total)

how will I compute for the area of the base of the roof??
I'm confused with that base which is a square 35 ft. 2 in. on a side. What's the meaning of that statement??

it means that the base is a square (all sides are equal length) with one side being 35'2"... how do you find an area of a square?

Originally Posted by Solarmew

it means that the base is a square (all sides are equal length) with one side being 35'2"... how do you find an area of a square?

I know that the base is a square which is 35 ft on each side, but what the use of 2in?

Can you compute it for me?, so I can see your solution..

what do you mean what's the use? XD it's the length 35feet and 2 inches XD ... you should convert it into inches to ease calculations :] (there are 12 inches in a foot)

Originally Posted by Solarmew

what do you mean what's the use? XD it's the length 35feet and 2 inches XD ... you should convert it into inches to ease calculations :] (there are 12 inches in a foot)

I will add the 2 measurement 35 ft and 26 ftto get the side is that what are you trying to say,.,Please explain it clearly I don't understand your explanation or you can compute it for me.

i dunno how much clearer to explain it X.X
you can type "what is 35 feet 2 inches in inches" in google and it'll tell you...

Originally Posted by Solarmew

i dunno how much clearer to explain it X.X
you can type "what is 35 feet 2 inches in inches" in google and it'll tell you...

Thanks,.I solve now the problem ^^

Can you teach me how to compute it manually

35 feet 2 inches = 35.1666667 feet

how it become 35.1666667?

there are 12 inches in one foot... it's easier to convert the length to inches, this way all you have to do is:

35*12(because there are 12 inches in a foot)+2(the remaining two inches)