- 1). Label each of the vertices on your shape using letters, starting with "A."
- 2). Label the coordinates for the line from "A" to "B." Label the "A" coordinates "X1" and "Y1," and label the "B" coordinates "X2" and "Y2."
- 3). Find the distance between "A" and "B." To do this, subtract "X1" from "X2." Then subtract "Y1" from "Y2." Then multiply each of these numbers to the second power. Then add these numbers together to get the measurement for this side.
- 4). Repeat Step 3 to find the distance between "B" and "C," "C" and "D," and so on, until you have found the measurements for all of the sides.
- 5). Add all of the sides together to find the perimeter.
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