Question

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=(13)b . Write two different expressions giving the perimeter of the donkey’s pen. 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. Explain why you used that expression to evaluate the perimeter of the donkey’s pen. Algebraic Expressions Portfolio Worksheet

Answer 1

Expression 1:

Perimeter = 2(a + b)

Expression 2:

Perimeter = 2(a + 13b)

Let's choose a value for b = 6.

a = (13)b

a = (13)(6)

a = 78

Using Expression 1:

Perimeter = 2(a + b)

Perimeter = 2(78 + 6)

Perimeter = 2(84)

Perimeter = 168

Explanation:

I used Expression 1 to evaluate the perimeter of the donkey's pen because it directly adds the values of a and b. Since we know the values of a and b, it is simpler to substitute these values into the expression and compute the result.