Subscribe to our FREE newsletter and start improving your life in just 5 minutes a day. Like many mathematical terms, the word perimeter has its origins in the work of early Greek mathematicians.
Perimeter is literally a measurement around. In everyday usage, you may have come across phrases such as perimeter fence , estate perimeter , or perimeter security. These mean that the fence, or the security provision, are around the edges, the outer limits or extremities of a measured area of land or property. Understanding how to calculate perimeter is a useful mathematical skill for both study and real life, whether performing geometric calculations, marking out a playing field or replacing a fence.
The definition of a boundary is a dividing line between two areas. In cricket, the boundary is the line marking the edge of the pitch.
The perimeter is the measured length of such a boundary. In geometry, it is defined as the sum of the distance of all the lengths of the sides of an object. Perimeter is measured in any unit of length, e. For more on this, see our page on measurement systems. So in common language, the two are often used interchangeably. However, in a mathematical context, we only use perimeter.
A circumference is a very specific type of perimeter, that refers only to circular shapes and forms. More on this later. The perimeter of a two-dimensional shape is the total length of all the sides added together. For example, the perimeter of a square, with a side length of 6m, is simply four lots of 6m, i.
The square has four sides of equal length, which are added together. Whilst perimeter is the measurement of the outline of the shape, area is the measurement of the space contained within the perimeter. So whilst perimeter is measured in units of length, area is measured in square units, e. For more on measuring area, see our page on Calculating Area. Improve this question. Add a comment. Active Oldest Votes. Improve this answer. See also: Helion below.
Hellion Hellion The real reason why you'd never hear that could be as phonixheart6 stated in his answer. However, I'd be constrained to say this is general reference question. Community Bot 1. Kris Kris Featured on Meta. Now live: A fully responsive profile. Related 1. For this class, that error is usually acceptable. However, you will find in other subjects such as physics or chemistry, that level of accuracy is a concept of great importance.
The radius of the moon is about miles. What is the circumference? Notice that our final results are different. That difference is the error created by using 3. When doing homework and tests, read the directions carefully on each problem to see which form to use. Find the circumference or perimeter given in each described situation below.
Include a drawing of the shape with the included information. Use the examples to help determine what shapes to draw. Show all work. As in the examples, if units are included then units should be present in your final result. Round to tenths unless indicated otherwise. The basic formulas for perimeter of straight-line shapes and the circumference of a circle will help us find the distance around more complicated figures.
Find the distance around the following shape. Round final answer to tenths and use 3. Wally wants to add a fence to the back of his house to make some room for his children to play safely see diagram below. He began measuring his yard but got distracted and forgot to finish measuring before he went to the store. If he remembers that the back wall of his house is 15 yards long, does he have enough information to buy the fencing he needs?
If so, how many feet should he buy? Wally successfully fenced his yard but now wants to add some landscaping and create a grassy area as shown below. He heads down to the local lawn store and finds out that in order to determine how much sod he needs, he must figure out the square footage of the area he wants to add grass to.
On his way home, he realizes that if he divides the grassy area into sections that are 1 foot by 1 foot and then counts them, he can determine the square footage. Here is the information Wally drew up when he got home. How do we find the area for shapes that are more complicated? Break up the areas into shapes that we recognize and add the area values together. If you look closely at the shapes in the previous examples, you might notice some ways to write each area as a more explicit formula.
Note that h is the straight-line distance from top of the triangle directly to the other side. The small box next to h indicates this. Circle with radius r. The area formula is the same. Example 10 Find the area for each described situation. Create a drawing of the shape with the included information. Use 3. Find the area given each described situation.
Round answers to tenths unless otherwise indicated. The basic formulas for area will help us find the area of more complicated figures.
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