Area of a Pentagon – Formula, Definition With Examples

Table of Contents

    Welcome to Brighterly, where we ignite the curiosity of young minds and lead them on an enlightening journey through the world of mathematics. Today, we’re diving into the geometric wonder that is the pentagon. The five-sided shape that has captured imaginations from the ancient Greeks to modern-day mathematicians, the pentagon is more than just a simple geometric figure. It’s a symbol of balance, beauty, and harmony. Whether you’re a student eager to unravel the mysteries of geometry or a parent looking to provide a stimulating educational experience, this comprehensive guide to the area of a pentagon is tailored for you. By understanding the properties, formula, and the way to calculate the area of this intriguing shape, you’re not just learning math – you’re unlocking a universe of possibilities with Brighterly.

    What is a Pentagon?

    A pentagon is a five-sided geometric figure that has intrigued mathematicians and geometry enthusiasts for centuries. It’s a simple yet profound shape that finds applications in various fields of design, art, and mathematics. A pentagon can be regular (with equal sides and angles) or irregular. The regular pentagon is often the most studied, as its symmetry lends itself to fascinating explorations in geometry. Understanding the pentagon, its properties, and how to calculate its area is an exciting journey into the world of shapes and spaces.

    Definition of Pentagon

    The pentagon is defined as a polygon with five sides and five angles. In a regular pentagon, all sides are of equal length, and all angles are of equal measure, usually 108 degrees. The term ‘pentagon’ comes from the Greek words ‘pente,’ meaning five, and ‘gonia,’ meaning angle. It’s a shape that’s been recognized and utilized in various cultures throughout history, from ancient Greek architecture to modern design.

    Definition of Area of a Polygon

    The area of a polygon refers to the total space enclosed within its boundaries. It’s a fundamental concept in geometry that helps in understanding how much space a particular shape occupies. Whether it’s a simple triangle or a complex decagon, every polygon has an area that can be calculated using specific formulas. The area is usually measured in square units, such as square centimeters or square inches. For children, imagining the area as a flat surface covered by a shape helps in visualizing this geometric concept.

    Properties of Pentagon

    The pentagon has some unique properties that distinguish it from other polygons. Some of the characteristics of a pentagon include:

    • Five sides and five angles
    • The sum of the internal angles is 540 degrees
    • In a regular pentagon, each angle is 108 degrees
    • A regular pentagon has five lines of symmetry
    • It can be divided into five congruent triangles

    Understanding these properties makes it easier to engage with the pentagon, whether in mathematical problems or creative applications like design and art.

    Properties of Area of a Polygon

    When dealing with the area of a polygon, there are certain properties to consider:

    • The area is always a positive value
    • The area is additive, meaning the sum of areas of non-overlapping parts equals the total area
    • Doubling the sides of a polygon quadruples its area
    • The unit of measurement for area is always in square units

    These properties hold true for all polygons, including pentagons, and form the basis for various mathematical calculations and applications.

    Difference Between Pentagon and Other Polygons

    While all polygons are multi-sided shapes, the pentagon stands out due to its five-sided structure. Here’s how it differs from other polygons:

    • Triangles: Three sides, sum of internal angles is 180 degrees
    • Quadrilaterals: Four sides, sum of internal angles is 360 degrees
    • Hexagons: Six sides, often seen in nature like in honeycomb patterns
    • Other Polygons: Varying number of sides and angles

    The pentagon sits uniquely between the quadrilateral and hexagon, embodying a balance of complexity and symmetry.

    Understanding the Formula for Area of a Pentagon

    The formula for the area of a pentagon might seem complex at first glance, but it’s derived from simple principles. By dividing the pentagon into five congruent triangles and finding the area of one of these triangles, you can multiply that area by five to get the total area of the pentagon. The use of the tangent function in the denominator is due to the unique angles within the pentagon, specifically the 72-degree angle that’s formed in each triangle.

    Calculation of the Area of a Pentagon Using the Formula

    Calculating the area of a pentagon is a matter of applying the formula. For a regular pentagon with a side length of 10 cm, you would:

    1. Insert the value into the formula: A = (5/4)*(100/tan(36))
    2. Calculate the value of tan⁡(36)
    3. Complete the calculation to find the area

    This step-by-step process can be a fun and educational exercise for students, helping them understand both the geometry of the pentagon and the principles of trigonometry.

    Practice Problems on Area of a Pentagon

    To master the calculation of the area of a pentagon, practice is key. Here are some problems to try:

    1. Find the area of a regular pentagon with side length 8 cm.
    2. Calculate the area of an irregular pentagon with given side lengths and angles.
    3. Design a regular pentagon within a circle and calculate its area.

    Solutions to these problems can be found by applying the formula and concepts discussed above, offering a hands-on approach to learning.


    As we conclude this geometric adventure with Brighterly, we hope that the world of pentagons has been unveiled to you in all its fascinating glory. From defining what a pentagon is to diving deep into its properties and learning how to calculate its area, we’ve embarked on a journey that transcends mere numbers and shapes. It’s a journey into understanding how the world is constructed, how balance and symmetry manifest themselves in nature, and how mathematics is a language that connects us to the universe. At Brighterly, our mission is to make mathematics engaging, accessible, and fun for children. The pentagon, with its five-fold beauty, is a testament to the wonder and joy that math can bring into our lives. Explore, learn, and grow with us, for the world of mathematics is a treasure trove waiting to be discovered. Thank you for choosing Brighterly as your guide into the magnificent realm of pentagons and beyond.

    Frequently Asked Questions on Area of a Pentagon

    What is a Regular Pentagon?

    A regular pentagon is a special type of pentagon where all five sides are of equal length, and all angles measure 108 degrees. It exhibits perfect symmetry, and its study can provide insights into various mathematical concepts. The regular pentagon is commonly found in art and architecture, symbolizing harmony and perfection.

    How is the Area of an Irregular Pentagon Calculated?

    Calculating the area of an irregular pentagon can be more complex, often requiring additional information like height or angles. One common method is to divide the pentagon into triangles and calculate the area of each, summing them up to find the total area. Different methods might apply depending on the given information, making this an exciting challenge in geometry.

    Why is the Pentagon Shape Important?

    The pentagon shape holds historical, cultural, and mathematical significance. From the architectural designs of ancient civilizations to the modern-day U.S. Department of Defense building, the pentagon shape resonates across domains. In mathematics, the regular pentagon is a source of fascination due to its unique geometric properties, and studying it opens doors to deeper understanding of symmetry, ratios, and space.

    Information Sources

    Kid’s grade

    • Grade 1
    • Grade 2
    • Grade 3
    • Grade 4
    • Grade 5
    • Grade 6
    • Grade 7
    • Grade 8
    Image full form