If tan x = 3/4 and 0◦ ≤ x◦ ≤ 90◦, then cos x =?
explain the work behind the solution

Last month, leonhard euler's watch kiosk at the mall had total sales of $9,489. merchandise totaling $225 was returned. the goods that were sold cost leonhard euler's $5,481. operating expenses for the moth were $992. what was the gross profit on sales?