II. This problem(and other pattern problems) may be solved using the list capabilities of the graphing calculator.

A. For instance, lets take a look at the following numbers from thepolygon problem

B. Now, select the STAT, Edit command on your TI-83. Press ENTER to see L1, L2, and so forth.

C. Clear the entries in L1 by placing your cursor directly on L1 and pushing CLEAR and then ENTER. In a similar manner, clear L2.

D. Now, in the L1 column, type 3, 4, 5, 6, 7.

E. Type 180, 360, 540, 720, 900 in the L2 column.

F. Now select 2nd, Y= to bring up the STAT PLOT menu.

1. Enter on Plot 1
2. Turn it on and select the first plot option(scatter plot).
3. Put L1 in Xlist and L2 in Ylist and choose the first mark.
4. Now select Zoom 9 to view this scatter plot.
5. What type of curve does it appear to be??

   G. Select STAT, CALC to see the various regression options.

6. Choose number 4 for linear regression.
7. When it appears on the screen, type the following immediately after it: L1, L2,
8. With the cursor behind L2, select VARS, Y-VARS, 1, 1, to put this regression into the Y1 function.
9. Finally, press enter
10. After noting the equation, press Y= to see the function.

    H. Press graph to view the line and the data.

    I. Shut off the STAT PLOT

    J. Select WINDOW from the top row. We would now like to determine the sum of the interior angles of a polygon with 25 sides.

11. Change the window as follows: Xmin=0; Xmax=30; Xscl=5; Ymin=0; Ymax=5000, Yscl=500
12. Press Graph to view
13. Select 2nd, TRACE to bring up the CALC menu
    • a. Choose 1 to enter a value for x
    • b. Now enter 25 to see the resulting y value
    • c. Find the sum for a polygon of 42 sides: