How did the egyptian workers cooperate to build to pyramids?

They are enslaved

At that time, building the pyramid was regarded as the most labor harsh architectural projects, considering the minimum technological development that exist at that time. Because of this, they obtained a lot of slaves from both Europe and Africa and force them as workers to build the pyramid.

explanation:

with the profits from the european sales, merchants purchased europe's manufactured  goods, including tools and weapons. then the merchants shipped those manufactured  goods, along with the  american  sugar and rum, to west africa where they were bartered for  slaves.

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