HELP QUICK!!! I Really need the answer l'll give you ten points.

Aparallelogram has an area of 216.24 cm2 and a height of 15.9 cm. how long is the base of the parallelogram? enter your answer as a decimal in the box. cm

You dug a hole that was 8 feet deep. after taking a short break, you dug down 3 more feet in the same hole. when finished digging, a tractor accidentally filled the hole with 4 feet of dirt. how deep is your hole now?

Which of the following is the major negative aspect of crossover designs for research studies? a. prohibitive cost b. residual effects c-subject drepout d. incomplete randomization e. large sample size required