Find the length of one side of a rhombus with diagonals 30 and 72

Find the simple interest earned to the nearest cent for each principal,interest rate,and time 735 7% and two and a half years

Suppose y varies directly with x. write a direct variation equation that relates x and y. then find the value of y when x=12 y=7 when x=3

Money off coupons have been circulated to 300 households. only 2/5 of these were redeemed (used) in the local supermarket to get a free shampoo. what fraction of coupons were unused? (ps: write how you got the answer)