Are you curious about perimeter and how it works in math? Then you've come to the right place! Perimeter is an important concept that helps us measure the length of the outside of shapes. In this blog post, we'll explore what perimeter is, how to calculate it, and its real-world applications.
What is perimeter?
When we talk about the perimeter of a shape, we're talking about the distance all the way around it. Imagine you draw a shape on a piece of paper and then trace your finger along the edge of the shape. The distance your finger traveled is the perimeter of the shape.
We measure the perimeter using things called "linear units," which just means we measure it in a straight line. For example, you might measure the perimeter of a shape using centimeters, meters, inches, or feet.
How to calculate Perimeter?
Let's say you have a square that's 4 inches on each side. If you add up all the sides, you get the perimeter. So, the perimeter of the square would be 4 + 4 + 4 + 4 = 16 inches.
How to Calculate the Perimeter of Basic Shapes
Perimeter of a Regular Shape
To calculate the perimeter of a regular shape, you simply need to multiply the length of one side by the number of sides the shape has. For example, if you have a square with sides of length 5 cm, the perimeter is:
Perimeter = 4 x 5 cm = 20 cm
If you have an equilateral triangle with sides of length 8 cm, the perimeter is:
Perimeter = 3 x 8 cm = 24 cm
And if you have a regular hexagon with sides of length 3 m, the perimeter is:
Perimeter = 6 x 3 m = 18 m
By using this simple formula, you can easily calculate the perimeter of any regular shape.
Perimeter of An Irregular Shape
An irregular polygon is a shape that doesn't have sides that are all the same length. To find the perimeter of an irregular shape, we have to add up all the sides. This is because there is no specific formula that we can use for irregular shapes like there is for squares or circles. So, we just have to add up all the sides to find the perimeter!
Therefore,
Perimeter of irregular polygon = sum of all sides.
Perimeter vs. Area: What's the Difference?
Perimeter
Area
Measures the length of the outside of a shape
Measures the space inside a shape
1-dimensional measurement
2-dimensional measurement
Measured in units of length (e.g. inches, meters)
Measured in units of area (e.g. square inches, square meters)
Add up the lengths of all sides to find it
Multiply the length and width of the shape to find it
Only considers the length of the boundary
Takes into account the entire shape
Changes with changes in shape size
Changes with changes in shape size and shape dimensions
Can be used to calculate the distance around a shape
Can be used to calculate the amount of material needed to cover a shape
Can be used to calculate fencing, tiling, or paving needs
Can be used to calculate the amount of paint or carpet needed to cover a shape
Can be represented by a single number
Can be represented by a single number, but may also be represented by a shape or graph
Only used for regular shapes with straight sides
Can be used for both regular and irregular shapes
Tricks for Calculating Perimeter Quickly and Accurately
Here are few tricks for calculating perimeter quickly and accurately, explained in simple terms!
Counting sides: One trick for finding the perimeter of a shape quickly is to count the number of sides it has. If it's a square, then you know it has 4 sides that are all the same length. If it's a rectangle, then you know it has 4 sides, but only the opposite sides are the same length. By counting the sides and using what you know about the shape, you can figure out the perimeter quickly.
Using a ruler: Another trick is to use a ruler to measure the sides of the shape. This way, you can make sure your measurements are accurate and you won't make any mistakes when adding them up.
Breaking it down: Sometimes, irregular shapes can be difficult to measure. But a trick for making it easier is to break the shape down into smaller shapes that are easier to measure. For example, you could break a weirdly shaped figure into triangles and rectangles, measure those shapes, and then add up the perimeters of each shape to get the total perimeter.
Using formulas: For shapes like circles, there are special formulas you can use to find the perimeter. By memorizing these formulas, you can quickly and accurately calculate the perimeter of circles and other shapes that have curved edges.
Real-Life Examples of Perimeter
Letâ€™s explore seven examples of how we use perimeter in everyday life, from measuring a classroom to building a fence around a garden.
Measuring the perimeter of a cricket field: The boundary line around a cricket field has a specific perimeter that determines the size of the playing area.
Building a fence around a garden: When building a fence around a garden, you need to measure the perimeter of the garden to know how much fencing material you need.
Measuring the perimeter of a classroom: The perimeter of a classroom is the distance around the walls. It can help you know how much paint or wallpaper you need.
Calculating the perimeter of a swimming pool: Knowing the perimeter of a swimming pool can help you determine how much pool fence you need to keep it safe.
Determining the perimeter of a park: The perimeter of a park is the distance around its outer boundary. It can help you estimate the size of the park.
Measuring the perimeter of a plot of land: If you're planning to build a house on a plot of land, you need to measure the perimeter to know how much fencing you need to secure it.
Determining the perimeter of a playground: The perimeter of a playground is the distance around the outside edge. It can help you determine how much material you need for a border around the play area.
Perimeter Problems and Solutions
Find the Perimeter of the given figure.
Perimeter of the square is twice theÂ size of the triangle. What is theÂ perimeter of the square?
Perimeter of a rectangle field isÂ 528 m. If the length of the field isÂ double the breadth then figure outÂ the length and breadth of the field.
Choose:
Arushi places a colored ribbonÂ around a pentagon shaped painting.Â The 3 sides are 8m and 2 sides are 9m.Â How many meters of ribbon areÂ needed for the perimeter?
What is the perimeter of the figureshown (all angles are right angles)?
A park shaped like a rectangle has a length of 24 meters and a width of 18 meters. If trees are planted on its sides with gaps of 2 meters between them, how many trees are needed?
Answers:
B. 70m
B. 60 in
A. 176m, 88m
A. 42m
D. 46
The perimeter of the rectangle is 2 Ă— (24 + 18) = 2 Ă— 42 = 84 meters, so there will be 84 Ă· 2 = 42 trees.