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Width: Definition, Examples, and Practice Math Problems

Jessica Kaminski

reviewed by Jo-ann Caballes

Updated on October 6, 2024

Welcome to another informative article on key math concepts from Brighterly!

Today, we’re going to cover the measurement of width in math.

We’ll cover the width definition geometry, the difference between width and length and width vs depth, plus the width of 2D and 3D shapes. We’ll also give you practice problems and worksheets so you can improve your knowledge.

What is width?

Width is a type of measurement that you’ll encounter in everyday life and in many math concepts. Below, we’ll cover the full width measurements definition.

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Width definition

The width definition geometry is a type of measurement that measures a distance or object from side to side.

Width in math is measured from one side to another – so as a width example, we measure the width of a doorframe by measuring from one side of the frame to the other.

What is the width and length: difference

You may have also heard of the measurement of length. So what’s the difference between length and width, and which way is length and width?

In both 2D and 3D shapes, the length will always refer to the longer side, and the width will refer to the shorter side. Think of a swimming pool – the length represents how far you’ll swim (i.e. your lengths), whereas the width is how wide it is. 

Take the length and width example below:

Is width and depth the same?

If you’re wondering, “are width and depth the same?”, the answer is no. The difference between depth and width is that depth is a measurement only used in 3D shapes; it is not a factor in 2D shapes. This is a side perpendicular to the width and height of your object.

Width of different 2D shapes

The width of 2D shapes refers to how wide they are, and in shapes that don’t have sides of equal length, the width measurements are defined as your shortest side.

Some 2D shapes that have a measurable width include:

• Squares – the width are the left and right-hand sides
• Rectangles – the width is your shortest side
• Triangles – the width is usually the base of your triangle
• Circle – more commonly known as the circumference

Other shapes require formulas to solve their width because of the irregularities of the shapes:

• Trapezoid – use the formula (base1 + base2) ÷ 2
• Pentagon – for a regular pentagon, multiply the length of one side by 0.62, or (√5 – 1)/2

Width of different 3D shapes

The width of 3D shapes tends to refer to the shorter of the three dimensions. 

Some 3D shapes that have a measurable width include:

• Sphere – because a sphere has no edges, the width, height and length all fall under the measurement of the radius
• Cube – the width of a cube is the same measurement as the height and length because it’s an equal-sided shape with equal-sized faces
• Cuboid – the width of a cuboid will be the shorter of the face measurements

Solved math tasks: examples

Now that you know what width measurements are and how to identify them, put yourself to the test with our math problems. Write down your answers, then check the solved answers and see how many you can get right.

Solved math task 1

Explain how you would identify the width of a 2D shape like a rectangle.

Answer:

Let’s use a width example: if we had a rectangle that had a pair of sides measuring 3cm and another pair of sides measuring 6cm, the width would be the shorter pair of 3cm.

Solved math task 2

Identify the width of the below shape:

Answer:

Solved math task 3

Identify the width measurement in the following shape:

Answer:

Width: worksheets

Ready to become a whizz at width measurements and other types of shape measurements? Try out our fun, free math worksheets to improve your knowledge even further:

• Shapes worksheets for kindergarten
• 3D shape worksheets for kindergarten
• 2D and 3D shapes worksheets
• Shapes worksheets

Jessica Kaminski

67 articles

Jessica is a a seasoned math tutor with over a decade of experience in the field. With a BSc and Master’s degree in Mathematics, she enjoys nurturing math geniuses, regardless of their age, grade, and skills. Apart from tutoring, Jessica blogs at Brighterly. She also has experience in child psychology, homeschooling and curriculum consultation for schools and EdTech websites.