Question 4
A’Leila is building a pen for her pet donkey. The pen is a rectangle with one side
measuring b yards and the adjacent side measuring a yards. A’Leila knows that
.
a. Write two different expressions giving the perimeter of the donkey’s pen.
b. Choose a value for a that is greater than 5 and less than 15. Evaluate the
perimeter of the pen for that value, using one of the expressions that you
wrote.
a.
Expression 1: P = 2a + 2b (perimeter is the sum of the lengths of all four sides)
Expression 2: P = a + a + b + b (perimeter is the sum of the lengths of the two lengths and two widths)
b. Let's choose a = 10.
Using Expression 1: P = 2(10) + 2b = 20 + 2b
Assuming b = 8: P = 20 + 2(8) = 20 + 16 = 36 yards