## Estimating the Area of Virginia

### Marking a Virginia state map

Directions:

A live map of Virginia appears at the bottom of this page.

Recall the coordinates of the southwest and southeast corners of Virginia are (24,98) and (474,98) respectively.  The state's length is therefore 450 pixels.  We need to mark eleven evenly spaced points on the northern boundary. Thus, our points needs to be 45 pixels apart (in the x -direction).

Point 1: Mark the point (24,98).

Point 2:  Locate and mark the point on the northern boundary that has x-coordinate 69.

Point 3:  Locate and mark the point on the northern boundary that has x-coordinate 114.

Do you see the pattern?

Points 4-10: Locate and mark the next 7 points on the northern boundary by increasing the x-coordinate by 45 for each point.  You must mark the points in order!

Point 11:  Mark the last point (474,98).

Now click the red "List points" button.  After a few seconds a new window will appear with the coordinates of the points you marked.  (You may need to enlarge the window).

Highlight the data in this window in the usual way by clicking and dragging or by using a combination of clicking and shift-clicking.

The next step is to copy-and-paste the highlighted data into your MAPLE worksheet.  You can copy by using control-c,  or by using the right mouse button and pop up menu.  Copy just the x-coordinates first. (Be sure you include both square brackets and the trailing semicolon in your copy as these are important pieces of the MAPLE syntax.)  Then paste the coordinates into the MAPLE worksheet at the end of the line containing  [> xborder :=   .  Now press the Enter key to activate and store these coordinates in MAPLE.

Then copy and paste the y-coordinates (including square brackets and semicolon) into your MAPLE worksheet  at the end of the line containing  [> yborder :=  Press Enter after this paste also.

Using this Live Map

• Click any place on the map to move the cursor to that point.

• Notice the readout at the upper right gives the location of the cursor measured in pixels from the lower left corner of the map.

• You can fine tune the location of the cursor by clicking on the four arrows at the left, right, top, and bottom of the map. Each click moves the cursor one pixel in the direction indicated by the arrow.

Sources:

The map used here was obtained at http://g-lea.tamu.edu/smap.htm.

The applet used here is described in the Lite Applets article and can be downloaded from the resources page at the end of the article.

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