Area of a hexagon

Here you will learn about the area of a hexagon, including how to find the area of regular hexagons and irregular hexagons.

Students will first learn about the area of a hexagon as part of geometry in high school.

What is the area of a hexagon?

The area of a hexagon is the amount of space inside a hexagon. A hexagon is a 2 D shape also known as a six-sided polygon.

Area of a regular hexagon

A regular hexagon is a polygon that has 6 sides of equal length and 6 equal interior angles.

The area of a regular hexagon can be found by splitting the shape into congruent triangles, by finding the midpoint of the shape and creating line segments.

You can find the area of one of the triangles and then multiply by the number of sides to find the total area of the regular polygon. This method will work for a regular hexagon, a regular octagon and so on. In the case of a regular hexagon, the triangles will be equilateral triangles.

The area of a regular hexagon can be simplified into the formula,

The area of the triangle can be found using the formula,

Where b is the base length (or the side of the hexagon) and h is the perpendicular height of the triangle. Sometimes these values will need to be calculated.

This means the area of a regular hexagon can also be written as,

Area of an irregular hexagon

An irregular hexagon may have been formed by different shapes. The area of a hexagon can be calculated by working out the area of each of these shapes and adding them together.

For example,

Area of the irregular hexagon ABCDEF is,

Angles in a regular hexagon

In order to work out the angles in a regular hexagon, you can use the angle fact that states ‘the sum of angles at a point is 360^{\circ}.

All 6 congruent triangles meet at the center of the hexagon, forming a point, therefore all 6 angles around that center point should sum to 360^{\circ}.

A regular hexagon can be split into 6 congruent equilateral triangles. So, the internal angles of an equilateral triangle are all 60^{\circ}.

The interior angles of these congruent triangles can be used in trigonometry to find the area of each of the equilateral triangles.

Two 60^{\circ} angles make one of the interior angles of a regular hexagon, so each of the 6 interior angles is 120^{\circ}.

What is the area of a hexagon?

Common Core State Standards

How does this relate to high school math?

• High School: Geometry (HS.G.MD.A.1)
  Use geometric shapes, their measures, and their properties to describe objects (e.g., modeling a tree trunk or a human torso as a cylinder).

• High School: Geometry (HS.G.SRT.D.11)
  Understand and apply the Law of Sines and the Law of Cosines to find unknown measurements in right and non-right triangles (e.g., surveying problems, resultant forces).

How to find the area of a hexagon

In order to find the area of a hexagon:

1. Consider the hexagon as a compound shape and split it appropriately.
2. Calculate the area of the parts.
3. Calculate the total area of the hexagon.
4. Write the answer, including the correct units.

Area of a hexagon examples

Example 1: irregular hexagon

Find the area of the irregular hexagon ABCDEF.

1. Consider the hexagon as a compound shape and split it appropriately.

You can split the ‘L’ shape into two rectangles.

2Calculate the area of the parts.

The area of the top rectangle is,

The area of the bottom rectangle is,

3Calculate the total area of the hexagon.

The total area of the hexagon is found by adding the area of the top and bottom rectangles together.

4Write the answer, including the correct units.

The dimensions of the shape are given in centimeters, so the units of the area will be in square centimeters.

The area of hexagon ABCDEF is 121 \ cm^2.

Example 2: irregular hexagon with inconsistent units

Find the area of the irregular hexagon ABCDEF.

Consider the hexagon as a compound shape and split it appropriately.

You can split the ‘L’ shape into two rectangles.

Calculate the area of the parts.

The dimensions of the top rectangle are both in meters.

The area of the top rectangle is,

\text{Area}=0.5\times 1.2=0.6.

To calculate the area of the bottom rectangle, be consistent and use meters. The area of the bottom rectangle is

\text{Area}=0.9\times (0.8-0.5)=0.27.

Example 3: area of a regular hexagon given the area of one of the equilateral triangles

Calculate the area of the regular hexagon ABCDEF given that the area of one of the congruent triangles is 14 \ m^2.

Example 4: area of a hexagon given the side length

Calculate the area of the regular hexagon ABCDEF given that the length of one side of a regular hexagon is 10 \ cm. Give your answer to 1 decimal place.

Consider the hexagon as a compound shape and split it appropriately.

Here, the regular hexagon ABCDEF has been split into six congruent equilateral triangles.

Calculate the area of the parts.

There are three methods you can use to find the area of an equilateral triangle by forming a right triangle with a right angle. The first two methods to find the height of the triangle are shown below.

The area of one of the equilateral triangles is,

\begin{aligned} A&=\cfrac{1}{2} \; bh\\\\ &=\cfrac{1}{2}\times 10\times 5\sqrt{3}\\\\ &=25\sqrt{3} \end{aligned}

The third method uses the HIGHER trigonometry formula for the area of a triangle.

\begin{aligned} A&= \cfrac{1}{2} \; ab \sin C \\\\ &=\cfrac{1}{2} \times 10\times 10\times \sin (60)\\\\ &=25\sqrt{3} \end{aligned}

Example 5: area of a hexagon given the height (apothem)

Calculate the area of the regular hexagon ABCDEF given that the length of the apothem of the regular hexagon is 12 \ cm. Give your answer to 1 decimal place.

Consider the hexagon as a compound shape and split it appropriately.

Here, the regular hexagon ABCDEF has been split into six congruent equilateral triangles.

Calculate the area of the parts.

You need to work out the base of the triangle.

This can be done using trigonometry with the angles inside the equilateral triangle.

x=12\div \tan(60)=4\sqrt{3}

The base of one of the equilateral triangles is,

\text{base}=2x=2\times 4\sqrt{3}=8\sqrt{3}.

The area of one of the equilateral triangles is,

\begin{aligned} A&=\cfrac{1}{2} \; bh\\\\ &=\cfrac{1}{2}\times 8\sqrt{3}\times 12\\\\ &=48\sqrt{3} \end{aligned}

Example 6: area of a hexagon given the radius of the circumcircle

Calculate the area of the regular hexagon ABCDEF given that the length from the center of the hexagon to the vertices is 20 \ cm. Give your answer in exact form.

Consider the hexagon as a compound shape and split it appropriately.

Here, the regular hexagon ABCDEF is split into six congruent equilateral triangles.

Calculate the area of the parts.

You need to work out the height of the triangle using trigonometry with the angles inside the equilateral triangle. The hypotenuse of the triangle is 20 \ cm.

\text{height}=\sin(60)\times 20=10\sqrt{3}

You need to work out the base of the triangle using trigonometry with the angles inside the equilateral triangle. The hypotenuse of the triangle is 20 \ cm.

x=\cos(60) \times 20=10

The base of one of the equilateral triangles is,

\text{base}=2x=2\times 10=20.

The area of one of the equilateral triangles is,

\begin{aligned} A&=\cfrac{1}{2} \; bh\\\\ &=\cfrac{1}{2}\times 20\times 10\sqrt{3}\\\\ &=100\sqrt{3} \end{aligned}

The alternative method uses the HIGHER trigonometry formula for the area of a triangle.

\begin{aligned} A&= \cfrac{1}{2} \; ab \sin C \\\\ &=\cfrac{1}{2} \times 20\times 20\times \sin (60)\\\\ &=100\sqrt{3} \end{aligned}

Teaching tips for area of a hexagon

• Before students can find the area of a hexagon, check for understanding of basic hexagon knowledge, including what it is and real life examples of the shape, such as a honeycomb or soccer ball.

• Encourage students to use technology tools, such as an area of hexagon calculator to check their work in real time. This can assist with students not forming misconceptions as they are getting feedback quickly.

• Allow students time to practice with different examples, working independently and with other students.

Easy mistakes to make

• Using incorrect units
  Remember that area is measured in square units. Square units include square centimeters (cm^2), square meters (m^2) and square millimeters (mm^2).

• Rounding answers too early
  It is important to not round decimals until the end of all the calculations. Rounding too early could result in an inaccurate answer.

• Confusing the dimensions being used
  It is important to make sure you keep track of which dimensions you have been given and which dimensions you are calculating. Pay attention to each step of your work and use any given diagrams as you work through the problem.

• Not providing the answer in the form requested
  It is important to leave your answer in exact form if asked to. This may involve square roots ( for example, \sqrt{2}) and/or \pi.

Related area lessons

• Area of a triangle
• Area of right triangle
• Area of an isosceles triangle
• Area of an equilateral triangle
• Area of an obtuse triangle
• Area of composite shapes
• Area of irregular shapes
• Area of a pentagon

The next lessons are

• 3 D shapes
• Area of a quadrilateral
• Volume
• Surface area

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