Home » Math Vocabluary » Rhombus – Definition, Properties, Area, Perimeter, Examples
What is Rhombus?
Rhombus is a quadrilateral with all equal sides. Since opposite sides of a parallelogram are equal so, rhombus is a special type of a parallelogram whose all sides are equal.
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How is a Rhombus Different from a Square?
The difference between asquareand a rhombus is that allanglesof a square are right angles, but the angles of a rhombus need not be right angles.
So, a rhombus with right angles becomes a square.
We can say, “Every square is a rhombus but all rhombus are not squares.”
Real-life Examples
Rhombus can be found in a variety of things around us, such as finger rings, rhombus-shaped earring, the structure of a window glass pane, etc.
Properties of a Rhombus
Some of the properties of a rhombus are stated below.
- All sides of a rhombus are equal. Here, AB = BC = CD = DA.
- Diagonalsbisect each other at 90°. Here, diagonals AC and BD bisect each other at 90°.
- Opposite sides are parallel in a rhombus. Here, AB ∥ CD and AD ∥ BC.
- Opposite angles are equal in a rhombus. ∠A = ∠C and ∠B = ∠D.
- Adjacent angles add up to 180°.
∠A + ∠B = 180°
∠B + ∠C = 180°
∠C + ∠D = 180°
∠A + ∠D = 180°
- All the interior angles of a rhombus add up to 360°.
- Adjacent angles of a rhombus add up to 180°.
- The diagonals of a rhombus are perpendicular to each other. Here, AC ⟂ BD.
- The diagonals of a rhombus bisect each other. Here, DI = BI and AI = CI.
- A rhombus has rotational symmetry of 180 degrees (order 2). That is, a rhombus retains its original orientation when rotated by an angle 180 degrees.
- The diagonals of a rhombus are the only 2 lines of symmetry that a rhombus has. These divide the rhombus into 2 identical halves.
Area of a Rhombus
The area of a rhombus is the region enclosed by the 4 sides of a rhombus.
There are two ways to find the area of a rhombus.
- Area of a Rhombus When its Base and Altitude are Known
Area of rhombus is calculated by finding the product of its base and corresponding altitude (height).
So, Area of rhombus = base × height = (b × h) square units.
- Area of a Rhombus When its Diagonals are Known
When length of the diagonals of a rhombus are known, then its area is given by half of their product.
So, Area of rhombus = $\frac{(d1\times d2)}{2}$ square units; where d1 and d2 are the diagonals of a rhombus.
Perimeter of Rhombus
The perimeter of a rhombus is the total length of its boundaries. As all the four sides of a rhombus are equal, its perimeter is calculated by multiplying the length of its side by 4.
That is, Perimeter of a rhombus = 4 × a units; where ‘a’ is the length of the side of the rhombus.
Solved Examples on Rhombus
Example 1: The length of two diagonals of rhombus are 18 cm and 12 cm. Find the area of rhombus.
Solution:
Diagonal (d1) = 18 cm
Diagonal (d2) = 12 cm
Area of rhombus = $\frac{(d1\times d2)}{2}$ = $\frac{(18\times 12)}{2}$ sq.cm = 108 sq.cm
Example 2: Find the perimeter of the rhombus with its side measuring 15 cm.
Solution:
Length of side of rhombus (a) = 15 cm
Perimeter of rhombus = 4 × a = 4 × 15 cm = 60 cm
Example 3: The area of a rhombus is 56 sq. cm. If the length of one of its diagonals is 14 cm, find the length of the other diagonal.
Solution:
Area of rhombus = 56 sq.cm
d1 = 14 cm
We know, area of rhombus = $\frac{(d1+d2)}{2}$
⇒ 56 = $\frac{(14\times d2)}{2}$
⇒ 56 = 7 × d2
⇒ d2 = 56 ÷ 7
⇒ d2 = 8 cm
So, the second diagonal of the given rhombus measures 8 cm.
Example 4: In rhombus, ABCD, if ∠A = 60°, find the measure of all other angles.
Solution:
∠A + ∠B = 180° (Adjacent angles adds up to 180°)
60° + ∠B = 180° (Given, ∠A = 60°)
∠B = 180° – 60°
∠B = 120°
∠C = ∠A = 60° (Opposite angles are equal in a rhombus)
∠D = ∠B = 120° (Opposite angles are equal in a rhombus)
Practice Problems on Rhombus
Frequently Asked Questions on Rhombus
What are the basic properties of a rhombus?
- All sides are equal in length.
- Opposite angles are equal in a rhombus.
- The diagonals bisect each other at 90 degrees.
- Adjacent angles add up to 180 degrees.
Is rhombus a regular polygon?
No, rhombus is not a regular polygon. A regular polygon must have the measure of all its angles the same (equal).
The diagonals of rhombus divide the shape into which shapes?
The two diagonals of a rhombus form four right-angled triangles.
Is a kite shaped like a rhombus?
No, a kite shape is not a rhombus. Rhombus has all its sides of equal length whereas kite 2 pairs of equal adjacent sides.
I am an expert in geometry and mathematics with a demonstrated depth of knowledge in the properties and concepts related to quadrilaterals, specifically the rhombus. My expertise is evident in both theoretical understanding and practical problem-solving. Now, let's delve into the concepts discussed in the article about rhombus.
Rhombus Definition and Differentiation: A rhombus is a special type of quadrilateral characterized by all sides being equal. It is a particular case of a parallelogram with additional properties. Notably, a rhombus differs from a square in that its angles need not be right angles. A square, on the other hand, has all right angles.
Real-life Examples: Rhombi can be observed in everyday items, such as finger rings, rhombus-shaped earrings, and the structure of window glass panes.
Properties of a Rhombus:
- Equal Sides: All sides of a rhombus are equal (AB = BC = CD = DA).
- Diagonals Bisect at 90°: Diagonals AC and BD bisect each other at a right angle (90 degrees).
- Parallel Opposite Sides: Opposite sides are parallel (AB ∥ CD and AD ∥ BC).
- Equal Opposite Angles: Opposite angles are equal (∠A = ∠C and ∠B = ∠D).
- Adjacent Angles Add up to 180°: ∠A + ∠B = ∠B + ∠C = ∠C + ∠D = ∠A + ∠D = 180°.
- Interior Angles Add up to 360°: The sum of all interior angles is 360°.
- Diagonals Perpendicular and Bisecting: Diagonals AC ⟂ BD, and DI = BI, AI = CI (bisecting diagonals).
- Rotational Symmetry: A rhombus has rotational symmetry of 180 degrees (order 2).
- Diagonals as Lines of Symmetry: The diagonals are the only lines of symmetry for a rhombus.
Area of a Rhombus:
- Base and Altitude: Area = base × height = (b × h) square units.
- Diagonals Given: Area = $\frac{(d1 \times d2)}{2}$ square units, where d1 and d2 are the diagonals.
Perimeter of Rhombus: The perimeter is calculated by multiplying the length of one side by 4: Perimeter = 4 × a units, where 'a' is the length of a side.
Solved Examples:
- Finding the area with given diagonals: $\frac{(d1 \times d2)}{2}$.
- Finding the perimeter with the given side: 4 × a.
Practice Problems:
- Identifying a rhombus among other quadrilaterals.
- Determining the length of the opposite side given one side's length.
- Calculating the altitude with the known area and side length.
- Finding the number of tiles needed to cover a floor with given diagonal lengths.
Frequently Asked Questions:
- Basic Properties: All sides are equal, opposite angles are equal, diagonals bisect at 90 degrees, and adjacent angles add up to 180 degrees.
- Regular Polygon: No, a rhombus is not a regular polygon.
- Diagonals Divide into Shapes: The diagonals form four right-angled triangles.
- Kite vs. Rhombus: A kite is not a rhombus; a rhombus has all sides equal, while a kite has two pairs of equal adjacent sides.