7th Grade Section
WME@Kimpton Middle

Area of a Parallelogram

A ParallelogramYou already know how to find the area of a rectangle. Now we will consider the area of a parallelogram.

Recall that a parallelogram is a quadrilateral (figure with four straight sides) whose opposite sides are all parallel. The diagram on the right shows the base and height of a parallelogram. The height is the length of a perpenticular line from the base to the opposite side (the distance between these two sides).

A rectangle is actually a special kind of parallelogram.

To find the area of a parallelogram, you observe that there is a rectangle that has the same area. Find the area of that rectangle and you are done.

  • A parallelogram is shown in the following diagram. You can drag the points to change the parallelogram.

  • In the above diagram:

    1. Click the button "Draw Height from E".
    2. Click the button "Cut the parallelogram" to split the parallelogram into two parts.
    3. Drag the parts to form a rectangle. Click button "Merge into a Rectangle" to form a rectangle. Click button "reset" to get the parallelogram back.
  • Now answer these questions.

    • Does the rectangle you formed have the same area as the parallelogram you started with?
             

    • Does the rectangle you formed have the same base and the same height as the parallogram?
             

    • Given the base b and height h, the area of the rectangle is:  ×    = 

  • Now it is time to



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