Who was the hellenistic (greek) mathematician who invented the compound pulley and is known for his work with the laws governing simple machines? a. pythagoras b. euclid c. archimedes d. hippocrates

Which source would best a historian understand the effect of the great chicago fire on families? a. a biography of a chicago family displaced by the fire b. a letter from a grandmother in new york to her family in chicago c. a newspaper editorial about families who were displaced d. an oral history dictated by an adolescent who fled the fire