A pentagon is a geometrical shape, i beg your pardon has five sides and five angles. Here, “Penta” denotes five and also “gon” denotes angle. The pentagon is among the species of polygons. The amount of every the internal angles because that a regular pentagon is 540 degrees.

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In Geometry, we study around different species of shapes. The two-dimensional form that is composed of right lines and interior angles is known as a polygon. The instances of polygon are:

Triangle (three-sided polygon)Quadrilateral (four-sided polygon)Pentagon (five-sided polygon)Hexagon (six-sided polygon)Heptagon (seven-sided polygon)Octagon (eight-sided polygon) and so on.

In this article, you can learn about the five-sided polygon dubbed “pentagon” with suitable definition, shape, sides, properties in addition to its perimeter and also area of a pentagon formula in detail.

Pentagon Definition


A pentagon is a polygon through 5 sides and also 5 angles. Words “pentagon” is comprised of two words, specific Penta and Gonia, which means five angles. Every the political parties of a pentagon fulfill with each other end to end to type a shape. Therefore,

The number of sides the a pentagon = 5

Pentagon shape

Like other polygons such as triangle, quadrilaterals, square, rectangle, etc., the pentagon is additionally a polygon that contains five sides and also five angles.

Depending ~ above the sides, angles, and also vertices, there are different species of pentagon shapes, together as

Regular and Irregular pentagonConvex and also Concave pentagon

Regular and also Irregular Pentagon

If a pentagon is regular, then all the sides space equal in length, and five angles are of same measures. If the pentagon walk not have equal side length and angle measure, climate it is known as one irregular pentagon.


Regular Pentagon

As identified above, a continual pentagon contains five congruent sides. Thus, we have the right to easily discover the perimeter that this form of pentagon. This deserve to be it was observed from the listed below given figure.


Here, every the 5 sides space equal so the perimeter that a regular pentagon is 5 times the length of any type of one of its sides.

Also, we have the right to divide a consistent pentagon into five comparable triangles as displayed below.


Thus, we can say that the area that a regular pentagon is same to the 5 time area of a triangle through sides the exact same as the pentagon.

Convex and Concave Pentagon

If all the vertices the a pentagon are pointing outwards, it is recognized as a convex pentagon. If a pentagon has at least one peak pointing inside, then the pentagon is well-known as a concave pentagon.


Pentagon Properties

Some nature of the pentagon room as follows:

In the pentagon, the amount of the interior angles is equal to 540°.If all the sides are equal and all the angles space of equal measure, climate it is a regular pentagon. Otherwise, it is irregular.In the constant pentagon, each inner angle steps 108°, and each exterior angle procedures 72°.An it is provided pentagon has 5 same sides.The sum of the internal angles the a rectangle-shaped pentagon is 540°.

Area the a Pentagon


For a regular pentagon with side and also apothem length, climate the formula to discover the area that a pentagon is offered as

Area the a Pentagon, A = (5/2) ×Side length ×Apothem square units

If just the side size of a pentagon is given, then

Area = 5s2 / (4 tan 36°) Square units

If just the radius the a pentagon is given, then

Area =(5/2)r2 sin 72° Square units

Perimeter the Pentagon

Since every the political parties “a” that a continual pentagon space of same measure, then the perimeter or one of a pentagon is composed as,

The perimeter of a pentagon, p = 5a units

Pentagon fixed problem

Question: Find the area and perimeter the a constant pentagon whose next is 5 cm and also apothem size is 6 cm.



The side of a pentagon, a = 5 cm

Apothem size = 6 cm

We know that

The area of a pentagon, A = (5/2) ×Side length ×Apothem square units

Substitute next = 5 cm, Apothem = 6 cm in formula,

A = (5/2) × 5 × 6

A = 5 × 5 × 3

A = 75

Therefore, the area that a pentagon is 75 cm2

The perimeter of a pentagon, ns = 5a units

P = 5(5)

P = 25 cm

Hence, the perimeter of a pentagon is 25 cm.Based top top the nature of pentagons, there space other types of pentagons the exist in geometry. They are:

1. It is provided pentagon

A polygon with 5 sides the equal length is called an equilateral pentagon. However, all the 5 internal angle of a pentagon deserve to take a range of sets of values. They are thus enabling it to type a household of pentagons. Therefore, the continual pentagon is distinct up to similarity. Since it is one equilateral and also equiangular (since its five angles room equal) pentagon.

2. Cyclic pentagon

If all the vertices that a pentagon lie on the one of a circle, climate it is called a cyclic pentagon. The continuous pentagon is the ideal example the a cyclic pentagon. The area the a cyclic pentagon have the right to be stood for as one 4th the square source of among the root of a septic equation. Here, the coefficients the the equation are features of the political parties of the pentagon. This uses to both regular and also irregular pentagons.

Line of symmetry of a Pentagon:

When coming to the heat symmetry, every polygon has a certain number of lines of symmetry. For example, a square has 4 present of symmetry. In the exact same way, a regular pentagon has 5 present of symmetry.

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