Area

1
Area

• The size of a surface in square units

2
Area of a Rectangle

• A rectangle with a length of 2 units and width of
  3 units has an area of 6 square units.

3
1
2
3
2
4
5
6

• The formula is
• Area of rectangle length x width

or base x height
3
Area of a Square

• A square is a rectangle with all sides the same,
  so the formula can be simplified.

2
1
2
2
3
4

• The formula is
• Area of square side x side

4
Area of a Triangle

• Suppose you have a triangle that is 3 units wide
  and 2 units high.
• Notice what shape a triangle makes if you cut it
  and copy the pieces.

height
Note that the height is always 90 degrees to the
base.
base

• It becomes a rectangle whose area is base x
  height.
• Notice that two whole triangles can fit into that
  same rectangle, meaning one triangle is only half
  of the area of that rectangle
• therefore Area of a Triangle (base x height)/2

5
Area of a Parallelogram

• Suppose you have a parallelogram that is 3 units
  wide and 2 units high.
• Notice what shape it makes if you cut off the end
  and put it on the other side.

height
base

• It becomes a rectangle whose area is base x
  height.
• therefore Area of a Parallelogram base x
  height

6
Area of a Trapezoid

• Suppose you have a trapezoid that is 7 units wide
  on the bottom, 1 wide on the top, and 2 units
  high.
• Notice what shape it makes if you cut off the
  ends at half the height and shift upwards.

1
4

• It becomes a rectangle whose base is (top
  bottom)/2.
• therefore Area of a Trapezoid (top bottom)/2
  x height

7
Summary

• Area of rectangle length x width

8
Summary

• Area of rectangle length x width
• Area of square side x side

9
Summary

• Area of rectangle length x width
• Area of square side x side
• Area of triangle (base x height)/2

10
Summary

• Area of rectangle length x width
• Area of square side x side
• Area of triangle (base x height)/2
• Area of parallelogram base x height

11
Summary

• Area of rectangle length x width
• Area of square side x side
• Area of triangle (base x height)/2
• Area of parallelogram base x height
• Area of trapezoid (top bottom)/2 x height

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