Arithmetic - Miscellaneous
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Finding the area of this type of shape is even trickier than what you saw in the previous lesson. As before there are two general approaches to finding the area. In each case you must figure out the area of rectangular areas and then you either add or subtract these areas depending on which method you use.
Method One: full_width * full_height - middle_height * middle_width

In this case you multiply the full width by the full height and then subtract away the product of the missing rectangle in the middle. Using the example we have:

  19 * 41 - 10 * 16 = 619 square cm
Method Two: full_height * width_1 + width_2 * height_2 + full_height * width_3

In this case the shape is divided into three vertical rectangles. The area of each rectangle is calculated and then these areas are added together.

  19 * 9 + 9 * 16 + 19 * 16 = 619 square cm
Obviously, either method we use will yield the same answer.
Alternatively, method two allows you to split the shape into horizontal rectangles like so:
  10 * 9 + 9 * 41 + 16 * 10  = 619 square cm
Remember area is always represented in square units.


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