Finding 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 . The formula is ; Area of rectangle = length x width or base x height 2 3 1 2 3 4 5 6 length width
- 3. Area of a Square A square is a rectangle with all sides the same, so the formula can be simplified. The formula is ; Area of square = side x side 2 2 1 2 3 4 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. 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 base height Note that the height is always 90 degrees to the base. 2 3
- 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. It becomes a rectangle whose area is base x height. therefore; Area of a Parallelogram = base x height base height 2 3
- 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. It becomes a rectangle whose base is (top + bottom)/2. therefore; Area of a Trapezoid = (top + bottom)/2 x height 1 4 2 7 4
- 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 bottom top height