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A quadrilateral is a polygon with four sides. To recall, the word ‘quad’ means four and the word ‘lateral’ means sides i.e. a quadrilateral is a figure bounded by four line segments such that no three of them are parallel to each other. A quadrilateral has four sides, four vertices, and four angles.
Rhombus and parallelogram are also considered quadrilaterals as they possess the basic property of quadrilaterals. But are these two shapes different from each other? Let’s find out the difference between a parallelogram and a rhombus in this article.
What is a Rhombus?
Rhombus is a four-sided two-dimensional quadrilateral with all its four sides equal in lengths. Rhombus is also referred to as a slanting square. Opposite sides of a rhombus are parallel. Rhombus is also called an equilateral quadrilateral, a diamond or a lozenge.
The properties of square and rhombus are similar, but the main distinguishing property is that square has all the angles equal to 90o, and rhombus does not. Also, all rhombus are not squares but all squares are rhombus.
Some of the important properties of a rhombus are as follows:
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The diagonals of a rhombus bisect each other and are perpendicular (forms right angle). They form scalene triangles.
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Opposite angles of the rhombus are equal and a diagonal bisects the internal angles.
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Adjacent sides are equal in lengths.
Consider the below figure of a rhombus we have,
()
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Sides AB = BD = DC = CA
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Diagonal ADCB
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Angle CAB = angle BDC and angle ACD = angle ABD
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As diagonal AD and BC bisects the opposite angles, so angle ABC = angle CBD and angle BCD = angle BCA
What is a Parallelogram?
A parallelogram is a four-sided two-dimensional quadrilateral whose opposite sides are parallel and congruent to each other. A parallelogram is also referred to as a slanting rectangle. Opposite interior angles of a parallelogram are of equal measures. The parallelogram and a rectangle are near about the same with one distinguishing property that the rectangle has all the angles of 900 while parallelogram does not. This means that all rectangles are parallelograms but the vice versa is not true.
Some of the important properties of a parallelogram are:
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Opposite sides are of equal length and are parallel to each other.
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Diagonals bisect the opposite angles.
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Diagonals bisect each other.
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Each diagonal bisects the parallelogram in two equal triangles.
Consider the below figure of a parallelogram we have,
()
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Side AC = side BD and side AB = side CD
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Side AB ∥ side CD and side AC ∥ side BD
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Angle CAB = CDB and angle ACD = angle ABD
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Diagonal AD bisects diagonal BC
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Diagonal BC bisects parallelogram in two equal triangles △ABC = △BCD
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Diagonal AD bisects parallelogram in two equal triangles △ ACD =△ABD
Difference Between Rhombus and Parallelogram
Rhombus and parallelograms are closely related to each other but they are still different. They are two different quadrilaterals. Some of the key difference between rhombus and parallelogram in the tabular form are:
Rhombus Vs Parallelogram
|
Sr. No |
Rhombus |
Parallelogram |
|
1 |
It is a 2-D figure with equal neighboring sides. |
It is a 2-D figure with equal parallel sides. |
|
2 |
All the four sides are of equal lengths. |
Opposite sides are of equal lengths. |
|
3 |
The area of rhombus is given by [frac {d_1 times d_2}{2}], where d1 and d2 are its diagonals. |
The area of a parallelogram is given by bh, where b and h are its base and height respectively. |
|
4 |
The perimeter of a rhombus is equal to P = 4a, where “a” is the length of each side. |
The perimeter of a parallelogram is equal to, given, P = 2 (a+b), where “a” is the side and b is the base. |
|
5 |
Diagonals bisect each other at right angle, forming two scalene triangles |
Diagonals bisect each other, forming congruent triangles |
|
6 |
Every rhombus is a parallelogram |
Every parallelogram is not a rhombus |
|
7 |
The term rhombus has originated from the Latin word with the meaning “to turn round and round.” |
The term parallelogram has originated from the Greek word “parallelogram” with the meaning “parallel lines”. |
How to Identify Whether a Quadrilateral is a Rhombus or a Parallelogram?
This is an obvious question every student has in their mind. To identify the nature of a quadrilateral, there are a few things we need to observe and do.
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First of all, measure the length of all sides. If the length of all sides are the same, it may be a square or rhombus, but never a parallelogram.
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Now check the diagonals if they bisect each other at right angles, and make the conclusion accordingly
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Last thing is to check the opposite angles.
Considering all these things, you can conclude your answer with proper justification.
Conclusion
Thus, we conclude that a rhombus is a special kind of parallelogram and that every rhombus can be a parallelogram but not vice versa. This is because in addition to parallel sides, rhombus also has all the sides equal, whereas in parallelogram opposite sides are parallel but adjacent sides size may not be the same.