Popular Branches
MBA
B.Tech
BBA
BSc
Updated on 02nd March, 2023 , 5 min read
A parallelogram is a quadrilateral (a flat figure with four sides) in which the opposite sides are parallel and equal to each other in length.
Area of Parallelogram can be defined as a region which is covered by a parallelogram in a two dimensional plane as a parallelogram is a two dimensional diagram with four sides. As per the definition, the area of the parallelogram is the region the figure covers on a plane and mathematically, it is equal to the product of length and height of the parallelogram.
The sum of a quadrilateral's interior angles is 360 degrees. A parallelogram consists of two pairs of parallel sides that are equal in measurement. Now that it is a two dimensional figure, a parallelogram has an area and a perimeter. Here in this article, we will discuss the area of parallelogram and its formula, how to derive it, and more examples of it in a detailed manner.
A Rectangle, Square, and Rhombus are all examples of a parallelogram. Geometry is all about two dimensional and three dimensional shapes. All these 2D and 3D shapes have a different set of properties with different formulae for area. The primary focus of this article will be on:
According to the definition, the Area of Parallelogram region enclosed by a parallelogram in a two dimensional plane. As we have discussed above, a parallelogram is a special type of quadrilateral with four sides and each pair of the opposite sides is parallel to each other. Besides, in a parallelogram, the opposite sides are equal in length and the opposite angles are of equal measures. Since the rectangle and the parallelogram have similar properties, the area of the rectangle is equal to that of the parallelogram.
To calculate the area of a parallelogram, multiply the perpendicular's base by its height. It should be noted that the parallelogram's base and height are perpendicular to each other, but the parallelogram's lateral side is not. As a result, a dotted line is used to represent the height.
Therefore,
Area = b x h Square Units |
Where -
b = base of the parallelogram
h = height of the parallelogram
In this article, mentioned below is the derivation of the area of a parallelogram.
The area of a parallelogram can be calculated using its base and height. Aside from that, the area of a parallelogram can be calculated if its two diagonals and any of their intersecting angles are known, or if the length of the parallel sides and any of the angles between the sides are known. As a result, there are three methods for calculating the area of a parallelogram:
If a and b are the set of parallel sides of a parallelogram and h is its height, then the formula for its area is given by:
Area = Base (b) x Height (h)
Area = b x h Square Units |
Example 1 - The base of a parallelogram is 5 cm and its height is 3 cm. Find the area of the parallelogram.
Solution 1 - Given,
Length of base = 5 cm
Height = 3 cm
Applying the formula of area of parallelogram -
Area = 5 x 3 = 15 sq.cm
In case, the height of a parallelogram is not given and not known to us, then we can use Trigonometry concept in order to find the area:
Area = ab sin (x)
Where a and b are the length of parallel sides and x is the angle between the sides of the parallelogram.
Example 2 - If the angle between any two sides of a parallelogram is 90 degrees and if the length of its two parallel sides is 3 cm and 4 cm respectively, then find the area of the parallelogram.
Solution 2 - Let a = 3 cm and b=4 cm
x = 90 degrees
Area = ab sin (x)
A = 3 × 4 sin (90)
A = 12 sin 90
A = 12 × 1 = 12 sq.cm.
Note: If the angle between the sides of a parallelogram is 90 degrees, then it is a rectangle.
We can also calculate the area of any parallelogram using its diagonals' lengths. As we know that there are two diagonals in a parallelogram and these diagonals intersect each other. Assume that the diagonals intersect each other at an angle ‘y', then we can calculate its area from the below mentioned formula:
Area = ½ x d1 x d2 x Sin (y)
The table mentioned below explains the summarized formulae of the area of parallelogram:
Using Base and Height |
A = b × h |
Using Trigonometry |
A = ab sin (x) |
Using Diagonals |
A = ½ × d1 × d2 sin (y) |
Where,
Note: In the above figure,
If the sides of a parallelogram have been given in the vector form then its area can be calculated using the measurement of its diagonals.
Suppose, vector ‘a' and vector ‘b' are the two sides of a parallelogram, such that the resulting vector is the diagonal of parallelogram.
Area of parallelogram in vector form = Mod of cross-product of vector a and vector b
A = | a × b |
Now, we have to find the area of a parallelogram with respect to diagonals, say d1 and d2, in vector form.
So, we can write;
a + b = d1
b + (-a) = d2
or
b – a = d2
Thus,
d1 × d2 = (a + b) × (b – a)
= a × (b – a) + b × (b – a)
= a × b – a × a + b × b – b × a
= a × b – 0 + 0 – b × a
= a × b – b × a
Since,
a × b = – b × a
Therefore,
d1 × d2 = a × b + a × b = 2 (a × b)
a × b = 1/2 (d1 × d2)
Hence,
Area of parallelogram when diagonals are given in the vector form, becomes:
A = 1/2 (d1 × d2)
where d1 and d2 are vectors of diagonals.