1. The size of a surface in square units
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
length 1 2 3 2 4 5 6
width
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
side 1 2 2 3 4
The formula is ;
Area of square = side x side
or side squared (side ) 2

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. 2
height
Note that the height is always 90 degrees to the base. 3
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. 2
height 3
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 2 7 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
length
width

8. Summary Area of rectangle = length x width
Area of square = side x side
side
side

9. Summary Area of rectangle = length x width
Area of square = side x side
Area of triangle = (base x height)/2
height
base

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
height
base

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
top
height
bottom