Perimeter is the length of all the outermost lines of the polygon, while area is the amount of space that fills the side. Area and perimeter are useful quantities that can be used in household projects, building projects, DIY projects (do-it-yourself or DIY), and estimates of materials that may be needed. For example, to paint a room, you need to know how much paint is needed or, in other words, how much area the paint will cover. The same can be applied when you need to measure a garden plot, build a fence, or do other chores around the house. In those situations, you can use the area and perimeter of a flat shape to save time and money when buying materials.
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Part 1 of 2: Looking Around
Step 1. Determine the flat shape you want to measure
Perimeter is an outline that surrounds a closed geometric shape. Different forms, different approaches. If the shape whose circumference you want to find isn't closed, you can't find the circumference.
If this is your first time calculating the perimeter, try calculating the perimeter of a rectangle or square. Basic shapes like these will make it easier for you to find the circumference
Step 2. Draw a rectangle on a sheet of paper
You can use these shapes as a form of practice to find the perimeter of the shapes. Make sure the opposite sides of the rectangle are the same length.
Step 3. Find the length of one of the sides of the rectangle
You can measure it using a ruler, tape measure, or make your own sample length of the sides. Write the number or size on the side represented so you don't forget. As a guide example, imagine that one side of your rectangle is 30 centimeters long.
- For smaller shapes, you can use centimeters, while meters are more suitable for calculating the circumference of larger shapes.
- Since the opposite sides of the rectangle are the same length, you only need to measure one side of the group of opposite sides.
Step 4. Find the width of one side of the shape
You can measure the width using a ruler, tape measure, or make your own sample. Write the number or size next to the horizontal side it represents.
Continuing the previous example guide, in addition to having a length of 30 centimeters, imagine that the shape you are drawing is 10 centimeters wide
Step 5. Write the exact measurements on the opposite sides of the shape
A quadrilateral has four sides, but the lengths of the opposite sides will be the same. This also applies to the width of the rectangle. Add the length and width used in the example (30 centimeters and 10 centimeters) to each opposite side of the rectangle.
Step 6. Add up the numbers from each side
On a piece of paper (or the paper you used to write the sample guide), write: length + length + width + width.
- Based on the example guide, you would need to write 30 + 30 + 10 + 10 to get the perimeter of the rectangle of 80 centimeters.
- You can also use the 2 x (length + width) formula for a rectangle because the length and width of the shape are doubled. For the previous example, you just need to multiply 2 by 40 to get the rectangle's perimeter of 80 centimeters.
Step 7. Adjust your approach for different flat shapes
Unfortunately, different shapes, different formulas are needed to find the circumference. In a real-life example, you can measure the outline of a closed geometric figure to find out what its circumference is. However, you can also use the following formulas to find the perimeter of other flat shapes:
- Square: length of one side x 4
- Triangle: side 1 + side 2 + side 3
- Irregular polygon: add the length of each side
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Circle: 2 x x radius OR x diameter.
- The symbol “π” represents the constant Pi (pronounced “pi” as usual). If you have a “π” button on your calculator, you can use that button to use the circumference formula more accurately. Otherwise, you can estimate the value of “π” as 3, 14 (or the fraction 22/7).
- The term "radius" (or radius) refers to the distance between the center of a circle and its outermost line (the circle), while "diameter" refers to the distance between two opposite points on the outermost line of the shape that passes through the center of the circle.
Part 2 of 2: Finding Area
Step 1. Determine the dimensions of the flat shape
Draw a rectangle or use the rectangle you created earlier when looking for the perimeter. In this example guide, you'll use the same length and width measurements as before to find the area of a flat shape.
You can use a ruler, a measuring tape, or find a sample of the quantity yourself. For this example guide, the length and width of the rectangle will be the same as the measurements previously used to find the circumference, which are 30 centimeters and 10 centimeters
Step 2. Understand the meaning of “broad”
Finding the area of a flat shape that is inside the perimeter is like dividing the empty space in the shape into square units of 1 per 1. The area of a flat shape may be smaller or larger than its circumference, depending on the shape.
You can divide the chart into one unit segment (eg in centimeters) vertically or horizontally if you want to get an idea of the area measurement of a plane figure
Step 3. Multiply the length of the rectangle by its width
For the guide example, you need to multiply 30 by 10 to get the area of a flat shape of 300 square centimeters. Units for area should always be written in square units (square meters, square centimeters, etc.).
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You can abbreviate writing "square units" as:
- Meter²/m²
- Centimeter²/cm²
- Kilometer²/km²
Step 4. Change the formula used according to the shape
Unfortunately, different geometric shapes, different approaches used to calculate the area of the wake. You can use the following formulas to find the area of some fairly common flat shapes:
- Parallelogram: base x height
- Square: side x side
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Triangle: x base x height
Some mathematicians use the formula: L = at
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Circle: x radius
The term "radius" (or radius) refers to the distance between the center of the circle and its outermost line (the circle), and the power of two (referred to as "square") indicates that the value to the power (in this case, the length of the radius) must be multiplied by the length of the radius itself
