MATH: Scaling Up for Area and Perimeter CALM U1 L6 9/28

In this exercise, you are given the area and perimeter of a blanket. Then, you are given ways to change the area and perimeter (for example, double the area and perimeter). Based on these changes, you are asked to find the new lengths and widths of the larger blanket. 

 

Tips (if you know the answers to the questions already just scroll past):

What is the first step to this whole exercise?

-The first step is to find the area and perimeter of the smaller blanket. 

 

What are the steps to finding length and width (dimensions) when given area and perimeter?

-Remember our factor pairs? First, list the factor pairs (the numbers needed to multiply together) to get the area. 

Let's say we have a rectangle with an area of 50 sq cm and a perimeter 30 cm.

Example: if the area is 50 sq. cm, then the factor pairs are 50 x 1, 25 x 2, and 10 x 5.

Next, you test each factor pair to see if they add up to the correct perimeter you're looking for. 

Perimeter = Length + Length + Width + Width

Factor pair 1: Perimeter is 30, so does 30 = 50 + 50 +1 + 1? That gives us a perimeter of 102 cm, so not this length and width!

Factor pair 2: Perimeter is 30, so does 30 = 25 + 25 + 2 +2? That gives us a perimeter of 54 cm, so not this length and width either!

Factor pair 3: Perimeter is 30, so does 30 = 10 + 10 +5 +5? That gives us a perimeter of 30 cm, we have now found the length and width that we are looking for!

Here is a video example of this process (If you are stuck, I highly recommend this video): https://www.khanacademy.org/math/pre-algebra/pre-algebra-measurement/prealgebra-perimeter/v/length-and-width-from-perimeter-and-area

 

Here is another video about length and width: https://www.khanacademy.org/math/pre-algebra/pre-algebra-measurement/prealgebra-perimeter/v/width-from-perimeter

You will notice that the column on the left side of the videos contains more examples if you want them.

Lesson Video