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Area of Parallelogram is the region or space occupied by a parallelogram in a two-dimensional plane. It is the space enclosed with the four sides of a parallelogram.
- Parallelogram is a type of quadrilateral formed by parallel lines.
- It is a closed polygon whose opposite sides are equal and parallel.
- Parallelogram is divided into there major types namely Square, Rectangle, and Rhombus.
Area of Parallelogram is the product of its base and height. Area of Parallelogram is calculated using the formula:
Area of Parallelogram = Base x Height |
Read More: NCERT Solutions for Class 9 Maths Areas of Parallelograms and Triangles
Key Terms: Parallelogram, Area of Parallelogram, Area of Parallelogram Formula, Length, Diagonal, Quadrilateral, Base, Height
What is Parallelogram?
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Parallelogram is a special type of quadrilateral entirely formed by parallel lines. A quadrilateral is said to be a parallelogram if its opposite sides are parallel and congruent.
- Parallelogram is a quadrilateral in which both pairs of opposite sides are parallel and equal.
- It has two intersecting and non-equal diagonals.
- The diagonals of a parallelogram bisect each other and divide it into two congruent triangles.
- Since the opposite sides are equal, the opposite angles of a parallelogram are also equal.
- Rectangle, Square, and Rhombus are the three types of Parallelograms in Geometry.
Area of Parallelogram
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Area of Parallelogram is the region occupied within the four sides of a Parallelogram in a two-dimensional plane.
- It is the number of square units that can fit within the parallelogram.
- Area of Parallelogram is equal to the product of its base and height.
- It is measured in square units such as square meters (m2), square cm (cm2), square feet (ft2), etc.
Area of a Parallelogram
In the given figure, the area of the parallelogram ABCD is the area occupied within its four sides.
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Area of Parallelogram Formula
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Area of Parallelogram is the product of the base and height of the parallelogram. The base and altitude of a parallelogram are perpendicular to each other. Area of Parallelogram Formula is given as follows:
Area of Parallelogram = b x h |
Where
- b: Base of Parallelogram
- h: Height of Parallelogram
Solved ExampleExample: What will be the area of a sheet in the shape of a parallelogram, if its base is 20 cm, and its height is 8 cm? Solution: Given that
Using the Area of Parallelogram Formula Area of Parallelogram = b x h Area of Sheet = b × h = (20) × (8) = 160 cm2 Thus, the area of the sheet is 160 in2. |
How to Calculate Area of Parallelogram?
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Area of Parallelogram can be calculated easily using its base and height. Area of Parallelogram can also be calculated if its two diagonals are given along with any of their intersecting angles. It can also be calculated if the length of the parallel sides is known, along with any of the angles between the sides.
Thus, there are three different ways to calculate the Area of Parallelogram:
- Using Base and Height
- Using Diagonals and their Intersecting Angle
- Using Length of Parallel Sides and Angle between them.
All three methods are explained in detail below.
Area of Parallelogram Using Base and Height
Area of Parallelogram is usually calculated by multiplying the base and height of the parallelogram. It is calculated using the given formula:
Area of Parallelogram = b x h |
Here, be refers to the Base of the Parallelogram while h refers to the Height of the Parallelogram.
Solved ExampleExample: Calculate the area of a parallelogram with the base as 5 cm and height as 3 cm. Solution: Given that,
Using the Area of Parallelogram Formula Area of Parallelogram = b x h Area of Parallelogram = b × h = 5 × 3 = 15 cm2 Thus, the area of the given parallelogram is 15 cm2. |
Read More: Areas of Parallelograms and Triangles Important Questions
Area of Parallelogram Using Diagonals and Intersecting Angle
There are two diagonals of a parallelogram that bisect each other and divide the parallelogram into two congruent triangles. Area of Parallelogram can also be calculated using the two diagonals and their intersecting angle. It is calculated using the given formula:
Area of Parallelogram = 1/2 x d1 x d2 sin(x) |
Where
- d1: First Diagonal of Parallelogram
- d2: Second Diagonal of Parallelogram
- y: Angle between Two Diagonals
Solved ExampleExample: Calculate the area of a parallelogram with the length of diagonals as 15.6 cm and 17.2 cm respectively. The angle of the intersection of the two diagonals is 120o. Solution: Given that
Using the Area of Parallelogram Formula, Area = 1/2 × d1 × d2 sin (x) Area of Parallelogram = ½ x 15.6 x 17.2 sin(120) = ½ x 15.6 x 17.2 x √3/2 = 232.37 cm2 Thus, the area of the given parallelogram is 232.37 cm2. |
Area of Parallelogram Using Lengths of Sides
Area of Parallelogram can also be calculated using the length of the parallel sides and the angle between them. In this method, the concept of trigonometry is used to find the area. It is calculated using the formula:
Area of Parallelogram = ab sin(x) |
Where
- a: First Side of Parallelogram
- b: Second Side of Parallelogram
- x: Angle between Sides a and b.
Solved ExampleQues. If the angle between the two sides of a parallelogram is 90o and the length of the two parallel sides are 4 cm and 3 cm respectively, calculate the area of the parallelogram. Solution: Given that,
Using the Area of Parallelogram Formula, Area of Parallelogram = ab sin(x) Area of Parallelogram = 3 x 4 x sin (90) = 12 sin(90) = 12 x 1 (sin 90o = 1) = 12 cm2 Thus, the area of the given parallelogram is 12 cm2. |
Read More: Areas of Parallelograms and Triangles MCQs
Area of Parallelogram in Vector Form
[Click Here for Sample Questions]Area of Parallelogram can also be calculated with the help of its diagonals when the sides of a parallelogram are represented in vector form. Considering there are two sides as vector a and vector b of a parallelogram then the resulting vector is the diagonal of a parallelogram. Area of Parallelogram in vector form using the adjacent sides is given using the formula:
Area of Parallelogram = | \(\vec{a}\times\vec{b}\)| |
Here \(\vec{a}\) and \(\vec{b}\) are the vectors representing two adjacent sides of the parallelogram.
In order to find the area of a parallelogram with respect to diagonals, suppose d1 and d2 are in vector form. Then,
\(\vec{a} + \vec{b} = \vec{d_1}\)
\(\vec{b} + (\vec{-a}) = \vec{d_2}\)
Or
\(\vec{b} - \vec{a} = \vec{d_2}\)
\(\Rightarrow\) \(\vec{d_1} * \vec{d_2} = (\vec{a} + \vec{b})(\vec{b} - \vec{a})\)
= \(\vec{a} * (\vec{b} - \vec{a}) + \vec{b} * (\vec{b} - \vec{a})\)
= \(\vec{a} * \vec{b} - \vec{a} * \vec{a} + \vec{b}* \vec{b} - \vec{b} * \vec{a}\)
Since\(\vec{a} * \vec{a} = 0\) and \(\vec{b} * \vec{b} = 0\)
\(\Rightarrow\) \(\vec{a} * \vec{b} = \vec{-b} * \vec{a}\)
Since \(\vec{a} * \vec{b} = \vec{-b} * \vec{a}\)
\(\vec{d_1} + \vec{d_2} = \vec{a} * \vec{b} - (-(\vec{a} * \vec{b}))\)
= \(2(\vec{a} * \vec{b})\)
Therefore, when diagonals are given in a vector form the area of a parallelogram can be stated as
Area of Parallelogram = \(\frac{1}{2}|(\vec{d_1} * \vec{d_2})|\) |
Where, \(\vec{d_1}\) and \(\vec{d_2}\) are the diagonals of the parallelogram.
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Things to Remember
- Paralleogram is a quadrilateral whose opposite sides are equal and parallel.
- Area of Parallelogram is the region occupied by a parallelogram within its four sides.
- It is the product of the base and height of the parallelogram.
- Area of Parallelogram = Base x Height
- Area of Parallelogram with Diagonals and Intersecting Angle is given as 1/2 x d1 x d2 sin(y).
- Area of Parallelogram with Length of Sides is given as ab sin(x).
- Area of Parallelogram in Vector Form is | \(\vec{a}\times\vec{b}\)|.
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Sample Questions
Ques. The area of a playground that is in the shape of a parallelogram is 2500 in2 and one of its sides is 250 m. Find out the corresponding altitude using the Area of Parallelogram Formula. (3 Marks)
Ans. Given that,
- Area of Playground = 2500 in2
- Sides of Playground = 250 in
Using Area of Parallelogram Formula,
Area of Parallelogram = Base x Height
Height = Area of Parallelogram/Base = 2500/250 = 10 in.
Therefore, the corresponding altitude of the playground is 10 in.
Ques. What are the different types of a Parallelogram? (3 Marks)
Ans. The different types of a parallelogram are as follows:
- Rectangle: Rectangle is a parallelogram that has two pairs of equal and parallel opposite sides and four right angles.
- Rhombus: Rhombus is a parallelogram that has four equal sides in which the opposite angles are equal.
- Square: Square is a parallelogram that has four equal sides and four right angles.
Ques. What is the formula for Area of Parallelogram? (3 Marks)
Ans. There are three methods to calculate the Area of a Parallelogram. These are as follows:
- Area of Parallelogram = b x h
- Area of Parallelogram = 1/2 x d1 x d2 sin(y)
- Area of Parallelogram = ab sin(x)
Where
- b = Base of the Parallelogram
- h = Height of the Parallelogram
- d1 = First Diagonal of the Parallelogram
- d2 = Second Diagonal of the Parallelogram
- y = Angle between the Diagonals
- a = First Side of the Parallelogram
- b = Second Side of the Parallelogram
- x = Angle between the Sides ‘a’ and ‘b’
Ques. What will be the area of a parallelogram if its base and height are 4 cm and 8 cm respectively? (3 Marks)
Ans. Given that,
- Base of Parallelogram = 4 cm
- Height of Parallelogram = 8 cm
Using the Area of Parallelogram Formula
Area of Parallelogram = b x h
Area of Parallelogram = b × h = 4 × 8 = 32 cm2
Thus, the area of the given parallelogram is 32 cm2.
Ques. Find the area of the parallelogram if the length of its adjacent sides is 20 cm and 25 cm and the measure of the angle between the adjacent sides is 34°. (3 Marks)
Ans. Given that,
- Length of First Side = 20 cm
- Length of Second Side = 25 cm
- Angle between Both Sides = 34o
Using the Area of Parallelogram Formula,
Area of Parallelogram = ab sin(x)
Area of Parallelogram = 20 x 25 x sin(34°)
= 500 x 0.55919
= 279.595 cm2
Thus, the area of the given parallelogram is 279.595 cm2.
Ques. Find the height and base of a parallelogram when the area of a parallelogram is 500 sq. cm and its height is twice its base. (3 Marks)
Ans. Given that,
- Area of Parallelogram = 500 cm2
- Height, h = 2 x Base = 2b
Using the Area of Parallelogram Formula
Area of Parallelogram = b x h
500 = b x 2b
2b2 = 500
b2 = 250
b = 15.8 cm
Height, h = 2 x b = 31.6 cm.
Therefore, the height of the parallelogram is 31.6 cm.
Ques. Find the base and height of a parallelogram when the base is thrice its height and the area is 192 cm2. (3 Marks)
Ans. Given that,
- Area of Parallelogram = 192 cm2
- Base, b = 3 x Height = 3h
Using the Area of Parallelogram Formula
Area of Parallelogram = b x h
192 = 3h x h
3 x h2 = 192
h2 = 64 = 8 cm
Since height is 8 cm, therefore base = 3 x h = 3 x 8 = 24 cm.
Thus, the base and height of the parallelogram are 24 cm and 8 cm respectively.
Ques. Find the area of a parallelogram when two parallel lines are 80 cm and 40 cm respectively and the angle between them is 56o. (3 Marks)
Ans. Given that,
- Length of First Side = 80 cm
- Length of Second Side = 40 cm
- Angle between Both Sides = 56o
Using the Area of Parallelogram Formula,
Area of Parallelogram = ab sin(x)
Area of Parallelogram = 80 x 40 x sin(56°)
= 3200 sin(56°) = 2652.9 cm2
Thus, the area of the parallelogram is 2652.9 cm2.
Ques. Calculate the area of a parallelogram whose diagonals are 18 cm and 15 cm, and the angle of the intersection is 43o between the diagonals. (3 Marks)
Ans. Given that,
- Length of First Diagonal = 18 cm
- Length of Second Diagonal = 15 cm
- Angle of Intersection = 43o
Using the Area of Parallelogram Formula,
Area = 1/2 × d1 × d2 sin (x)
Area of Parallelogram = ½ x 18 x 15 sin(43o)
= 135 sin(43o) = 92.07 cm2
Thus, the area of the given parallelogram is 92.07 cm2.
Ques. A parallelogram with two parallel sides of 30 cm and 40 cm with an angle between the two sides as 36o. If the base of the parallelogram is 40 cm, find the height. (3 Marks)
Ans. Given that,
- Length of First Side = 30 cm
- Length of Second Side = 40 cm
- Angle between Both Sides = 36o
- Base of Parallelogram = 40 cm
Using the Area of Parallelogram Formula,
Area of Parallelogram = ab sin(x)
Area of Parallelogram = 30 x 40 x sin(36°)
It is also known as the Area of Parallelogram is also equal to Base x Height. Thus,
30 x 40 x sin(36°) = 40 x H
1200 sin(36°) = 40 x H
Dividing both sides by 40,
H = (1200/40) sin(36°)
H = 30 sin(36°) = 17.63 cm
Therefore, the height of the parallelogram is 17.63 cm.
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