The Great Pyramid of King Khufu was built of limestone inEgypt over a 20-year time period from 2580 BC to 2560 BC.Its base is a square with side length 756 ft and its heightwhen built was 481 ft. (It was the tallest man-made structurein the world for more than 3800 years.) The densityof the limestone is about 150 lb /  cu . ft  .(a) Estimate the total work done in building the pyramid.(b) If each laborer worked 10 hours a day for 20 years, for340 days a year, and did 200 ft - lb / h of work in liftingthe limestone blocks into place, about how many laborerswere needed to construct the pyramid?

The Great Pyramid of King Khufu was built of limestone in
Egypt over a 20-year time period from 2580 BC to 2560 BC.
Its base is a square with side length 756 ft and its height
when built was 481 ft. (It was the tallest man-made structure
in the world for more than 3800 years.) The density
of the limestone is about 150 lb /  cu . ft  .
(a) Estimate the total work done in building the pyramid.
(b) If each laborer worked 10 hours a day for 20 years, for
340 days a year, and did 200 ft - lb / h of work in lifting
the limestone blocks into place, about how many laborers
were needed to construct the pyramid?