SUMMARY

TIPS AND TREATS
(Distance cousin to trick-or-treat)

Below is a summary of all of the Thinking Inside The Box techniques. It is a list of TIPS on how to TREAT some shape measurements as the width or height so that you can easily determine or estimate the areas of the most common 2D geometric shapes.

BOTTOM LINE: MANY SHAPES, ONE FORMULA

Except for the rectangle shape, treat one or both sides (height/width/base), diameters, diagonals, or median depending on the shape as a height and/or width and use the rectangle formula with a "twist" instead of the shape traditional formula (for example, divide result by 2 for some or multiple by 0.8 for a circle).

Quadrilaterals

Trapezoid

1. Treat the median as the width.
2. Use the rectangle formula instead:
   Area_Trapezoid = height x width
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Kite

1. Treat the two diagonals as the height and width.
2. Use the rectangle formula instead:
   Area_Kite = height x width
3. Divide the result by 2.
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Square*

1. Treat any side (S) as both the height and the width since they are the same.
2. Use the rectangle formula instead:
   Area_Square = height x width
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Rectangle*

1. Simply use the rectangle formula:
   Area_Rectangle = height x width

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Rhombus*

1. Treat the altitude as the height and
   S as the width since they are all the same length.
2. Use the rectangle formula instead:
   Area_Rhombus = height x width
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* A square, rectangle, and rhombus are all parallelograms.

Triangles

Right / Acute / Obtuse

1. Treat the base as the width.
2. Use the rectangle formula instead:
   Area_Triangle= height x width
3. Divide the result by 2.
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Circle

Circle

1. Treat the diameters as both the height and the width.
2. Multiply the diameter by itself to get the total area
   of a square around the circle.
3. Multiply the total area of the square by 0.80 (80%)
   to get an approximate area of the circle:
   Area_Circle is approximately AreaOfSquare x 0.80
   
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