In order to find the perimeter, we need to know the lengths of all 4 sides of the parallelogram. We know two of the sides from the graph. How can we find the lengths of the other two sides?
Draw a triangle so that the missing side is the hypotenuse of the triangle. Then use the Pythagorean Theorem to find the length of the hypotenuse.
1² + 2² = hypotenuse²
1 + 4 = hypotenuse²
5 = hypotenuse²
Now add all the sides together to get the perimeter of the parallelogram.
Does the answer repeat or terminate?
Use the eTool below to graph the points and create a parallelogram.
Click the link at right for the full version of the eTool: MC2 11-72 HW eTool