A rhombus is a quadrilateral that has four equal sides. The term ‘rhombus’ has been derived from the Greek word ‘rhombos’ meaning something that spins. A rhombus is considered to be a special type of parallelogram because the opposite sides of a rhombus are parallel to each other, and all of the sides are equal in length. This means that all rhombuses are parallelograms, but all parallelograms are not rhombuses. Also, all the four angles of a rhombus are not necessarily right angles. Hence, a square is a rhombus with all angles equal to 90 degrees. This means that all squares are rhombuses, but all rhombuses are not squares. The area of a rhombus can be calculated by evaluating (½ d1 x d2); where d1 and d2 are the diagonals of the rhombus, and its perimeter or the length of the outer boundary is given as four times the length of one side. In simple terms, a rhombus is a two-dimensional image that is formed by stretching a square by holding two of its opposite corners.

**Properties of Rhombus**

1. The opposite sides of a rhombus are parallel to each other.

2. The opposite angles of a rhombus are congruent by nature.

3. The diagonals of a rhombus bisect each other.

4. The sum of two adjacent or consecutive angles of a rhombus is equal to 180°.

**Examples of Rhombus**

### 1. Brand Logos

Some of the brand logos make use of the rhombus geometric shape. For instance, the logo of Mitsubishi Motors Corporation, a Japanese multinational automotive manufacturing company comprises three rhombuses that are attached to each other at one vertex.

### 2. Kite

A kite is a prominent example of a rhombus geometric shape in real life because it typically consists of four sides that are equal in magnitude and four unequal angles.

### 3. Diamond

The shape of a rhombus can be pictured easily by looking at the outer boundary of a diamond. Also, the diamond shape drawn on the playing cards is yet another example of a rhombus geometric shape in real life.

### 4. Buildings

Some of the buildings such as the Adidas Flagship Building located in Herzogenaurach is shaped like a rhombus. Also, other architectures such as Chicago’s famous skyscraper is shaped like a diamond or a rhombus.

### 5. Jewellery and Accessories

A number of accessories and pieces of jewellery resemble the shape of a rhombus. For instance, earrings, rings, pendants, etc., are shaped like a rhombus.

### 6. Sign Board

Signboards are constructed in a variety of shapes out of which one of the most popular geometric shapes is a rhombus.

### 7. Gardening Tools

Some of the gardening tools used to dig holes in the earth are shaped like a rhombus.

### 8. Spear Blade

If you look closely at the shape of a spear blade, it is a quadrilateral that consists of four equal sides. This makes the spear blade a prominent example of rhombus-shaped objects used in real life.

### 9. Mats

Some of the doormats and carpets are also shaped like rhombus.

### 10. Tiles

Tiles come in a variety of shapes and sizes. One of the most popular shapes in which a tile is manufactured is the rhombus.

### 11. Cardigan Patterns

The patterns formed on the cardigans with the help of wool are sometimes shaped like a rhombus.

### 12. Key Chains

Key chains are available in a variety of shapes such as oval, square, rectangle, triangle, and rhombus.

### 13. Cookies

Cookies form a great example of rhombus-shaped objects present around us.

### 14. Baseball Field

Rhombus geometric shape can be easily observed in real life by looking at the quadrilateral section of a baseball field.

### 15. Mirrors

Mirrors are yet another example of rhombus-shaped objects used in everyday life.

I could use a book in Euclidean Geometry. Any suggestions?