Here are some lengths and widths of a rectangle whose perimeter is 20 meters.

1. Complete the table. What do you notice about the areas?

   length (meters)	width (meters)	area (square meters)
   1	9
   3	7
   5
   7
   9

2. Without calculating, predict whether the area of the rectangle will be greater or less than 25 square meters if the length is 5.25 meters.

3. On the coordinate plane, plot the points for length and area from your table.

   Do the values change in a linear way? Do they change in an exponential way?

   

   A blank graph, origin O, with a grid. Horizontal axis, length, meters, scale 0 to 15, by 3’s. Vertical axis, area, square meters, scale 0 to 30, by 5’s.

The table shows the relationship between \(x\) and \(y\), the side lengths of a rectangle, and the area of the rectangle.

Copies of a book are arranged in a stack. Each copy of a book is 2.1 cm thick.

The value of a phone when it was purchased was \$500. It loses \(\frac{1}{5}\) of its value a year.

1. What is the value of the phone after 1 year? What about after 2 years? 3 years?
2. Tyler says that the value of the phone decreases by \$100 each year because \(\frac{1}{5}\) of 500 is 100. Do you agree with Tyler? Explain your reasoning.

Technology required. The data in the table represents the price of one gallon of milk in different years. 

Give a value for \(r\) that indicates that a line of best fit has a negative slope and the variables are strongly correlated.