While correcting his math homework, a student notices his eraser is shaped like a parallelogram. He sketches it as parallelogram ABCD. One of the four sides of the parallelogram measures 5cm, and a second side measures 1.25cm. What is the perimeter of ABCD? A) 5 B)6.25 C)7.5 D)12.5 E)20

Sanya noticed that the temperature was falling at a steady rate of 1.4 degrees every hour from the time that she first checked her outdoor thermometer. by 6 a.m., the temperature had fallen 21 degrees. which expression can you use to find how many hours earlier she had first checked the thermometer?