For calculating area of a parallelogram easily, convert the diagram of parallelogram into a rectangle by extending or sketching different lines. Then use rectangle area formula and triangle area formula to calculate the area of the parallelogram.
Example
What is the area of parallelogram ABCD?
Solution:
See the math diagram in question. If you extend line AD and drop a perpendicular from point C, then it will become a perfect rectangle.
Now draw lines CE and DE to form rectangle ABCE.
Use rectangle area formula to calculate the area of rectangle ABCE
Area of rectangle ABCE = (width) (height)
Area of rectangle ABCE = 10 x 5
Area of rectangle ABCE = 50
Use triangle area formula to calculate the area of triangle CDE
Area of triangle CDE = ½ (height) (base)
Area of triangle CDE = ½ (5) (10 – 6)
Area of triangle CDE = ½ (5) (4)
Area of triangle CDE = 10
Now for calculating the area of parallelogram, subtract the area of rectangle from the area of triangle
Area of parallelogram ABCD = area of rectangle – area of triangle
Area of parallelogram ABCD = 50 – 10
Area of parallelogram ABCD = 40
Area of triangle CDE = ½ (5) (4)