how to find a perimeter of a rectangle

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The perimeter of a rectangle is the sum total length of all of its sides.^[1] A rectangle is defined as a quadrilateral, or a geometric shape with 4 sides. In a rectangle, both sets of opposite sides are congruent, meaning that they are the same length.^[2] While not all rectangles are squares, all squares can be considered rectangles, and a compound shape may be composed of rectangles.^[3]

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Write down the basic formula for finding the perimeter of a rectangle. This formula will help guide you as you calculate the perimeter of your own rectangle. The basic formula is: P = 2 * (l + w).^[4]
- Perimeter is always the total distance around the outside border of any shape, whether it is simple or chemical compound.
- In this equation, P stands for "perimeter," l refers to the length of the rectangle, and w refers to the width of the rectangle.
- Length always has a greater value than width.
- Because opposite sides of a rectangle are equal, both lengths will be the same and both widths will exist the same. This is why you write the equation as a multiplication of the sum of the length and width by 2.
- Yous can as well write the equation as P = l + l + w + west to make this very clear.
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Find the length and the width of your rectangle. For a bones math problem at school, the length and width of the rectangle will be provided in the problem. These are usually side by side to the figure of the rectangle.
- If yous are calculating the perimeter of a rectangle in real life, use a ruler, yardstick, or tape measure to find the length and width of the area that you are trying to measure. If yous're measuring outdoors, measure all sides to see if the opposites are truly coinciding.
- For example, l = 14 centimeter (5.v in), w = 8 centimeter (3.1 in).
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Add the length and width. ^[5] After you place your length and width, you want to plug them into the "50" and "w" slots in the perimeter equation.
- When you are working out your perimeter equations, note that according to the order of operations, mathematical expressions contained inside brackets or parentheses are solved before those outside of the parentheses.^[6] So, you lot'll begin solving your equation by calculation the length and width.
- For example, P = 2 * (l + w) = 2 * (fourteen + 8) = 2 * (22).
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Multiply the sum of the length and width by two. When yous're looking the formula for the perimeter of a rectangle, the "(fifty + due west)" is multiplied past two. Once you lot've completed this multiplication, you have the perimeter of your rectangle.
- This multiplication takes into account the other two sides of your rectangle. When you added together the width and length, you only added together ii sides of the shape.
- Since the other two sides of the rectangle are equal to the ii already added together, you lot can just multiply this measurement by two in order to find the total sum of all four sides.
- For example, P = 2 * (l + w) = 2 * (14 + eight) = 2 * (22) = 44 centimeter (17.3 in).
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Add fifty + l + w + w. Instead of adding two sides of your rectangle and multiplying by two, you can simply add all four sides together straight to find the perimeter of your rectangle.
- If yous struggle with the concept of perimeter, this is a slap-up place to start.
- For example, P = fifty + 50 + w + westward = 14 + 14 + viii + 8 = 44 centimeter (17.3 in).

1
Write downwards the formula for area and the formula for the perimeter of a rectangle. ^[7]Fifty-fifty though you lot already know the area of the rectangle in this trouble, you will still demand to use the surface area formula to find missing data.
- The expanse of a rectangle is a measurement of the two-dimensional space within the rectangle, or the number of square units inside the rectangle.^[viii]
- The formula used to find the area of a rectangle is A = fifty * w.
- The formula used to observe the perimeter of a rectangle is P = 2 * (l + w)
- In the above formulas, A stands for "area," P stands for "perimeter," l refers to the length of the rectangle, and w refers to the width of the rectangle.
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Divide the total surface area past the side measurement y'all know. This will let you to find the measurement of the missing side of your rectangle, whether it is the length or the width. Finding this missing piece of information will and then let you to calculate perimeter.
- Because you multiply the length and width together to detect the area, dividing the area past the width will give yous the length. As well, dividing the area by the length volition requite yous the width.
- For example, A = 112 centimeter (44.ane in) squared, l = xiv centimeter (5.5 in)
  - A = 50 * w
  - 112 = fourteen * west
  - 112/14 = westward
  - 8 = w
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Add the length and width. Now that you accept measurements for both the length and width, you lot can plug them into the formula for rectangular perimeter.
- In this trouble, you add together length and width together first because this part of the equation occurs in parentheses.
- Co-ordinate to the social club of operations, you always practice the part of the equation in parentheses starting time.
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Multiply the sum of the length and width by two. Once yous've added the length and width of your rectangle together, yous can detect its perimeter by multiplying by two. This takes into account the additional 2 sides of your rectangle.
- Y'all are able to find the perimeter of the rectangle by adding length and width and multiplying past two because the opposite sides of a rectangle are equal in length.
- Both lengths of the rectangle are the same, and both widths are the same.
- For case, P = two * (14 + viii) = 2 * (22) = 44 centimeter (17.3 in).

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1
Write downwards the basic formula for perimeter. ^[ix] Perimeter is the sum full of all outer sides of any given shape, including irregular and compound shapes.
- A standard rectangle has four sides. The 2 sides composing the length are equal to each other, and the two sides composing the width are equal to each other. Therefore, the perimeter is the sum of those four sides.
- A chemical compound rectangle has at least six sides. Think of a capital letter "Fifty" or "T" shape. The top "co-operative" can be separated into one rectangle and the lesser "bar" can be separated into another. The perimeter of this shape, however, does not rely on breaking upwards the compound rectangle into 2 separate rectangles. Instead, the perimeter is merely: P = s1 + s2 + s3 + s4 + s5 + s6.
- Each "s" represents a different side of your chemical compound rectangle.
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Discover the measurement of each side. In a standard educational math problem, the measurement of all sides should be provided.
- This instance uses the abbreviations L, W, l1, l2, w1, and w2. The uppercase L and W correspond the full lengths and widths of the shape. The lowercase ls and ws stand up for the smaller lengths and widths.
- As such, the formula P = s1 + s2 + s3 + s4 + s5 + s6 equals P = L + W + l1 + l2 + w1 + w2.
- Variables, like "west" or "l" are simply placeholders for unknown numeric values.^[10]
- Instance: L = 14 centimeter (five.5 in), Due west = 10 centimeter (iii.9 in), l1 = v centimeter (2.0 in), l2 = 9 centimeter (3.5 in), w1 = 4 centimeter (1.half dozen in), w2 = 6 centimeter (ii.4 in)
  - Note that l1 and l2 will equal L. Similarly, w1 and w2 volition equal W.
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Add together all the sides together. By plugging the numeric values of the sides into your equations, y'all'll be able to find the perimeter of your chemical compound shape.
- P = Fifty + W + l1 + l2 + w1 + w2 = xiv + 10 + v + 9 + 4 + 6 = 48 centimeter (18.9 in)

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Organize the information you do have. You lot can yet find the perimeter of a compound rectangle every bit long as you have at least one total length or total width and at to the lowest degree three of the minor width or length measurements.^[11]
- For an "50"-shaped compound rectangle, use the formula P = Fifty + W + l1 + l2 + w1 + w2
- In this formula, P stands for "perimeter." The uppercase L and West correspond the total lengths and widths of the entire compound shape. The lowercase ldue south and due wests stand for the smaller lengths and widths in the chemical compound shape.
- Case: 50 = 14 centimeter (5.5 in), l1 = 5 centimeter (two.0 in), w1 = 4 centimeter (1.6 in), w2 = 6 centimeter (2.4 in); missing: W, l2
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Use the measurements you have to find the missing side measurements. In this example, the total length, L, volition exist equal to the sum of l1 and l2. As well, the total width, Due west, volition exist equal to the sum of w1 and w2. Using this noesis, add and subtract the measurements y'all do have to observe the ii missing measurements.
- Example: L = l1 + l2; Due west = w1 + w2
  - 50 = l1 + l2
  - xiv = v + l2
  - xiv – v = l2
  - 9 = l2
  - W = w1 + w2
  - West = 4 + half dozen
  - W = 10
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Add your sides together. Once yous have subtracted to notice your missing measurements, you can add all of your sides together to find the perimeter of the compound rectangle. At present, you'll use the original perimeter formula.
- P = L + Westward + l1 + l2 + w1 + w2 = 14 + ten + 5 + 9 + 4 + 6 = 48 centimeter (18.9 in)

Add New Question

Question

How can I find the side of a rectangle if perimeter is given?

Y'all can't. With whatsoever given perimeter, an infinite number of length-width combinations would be possible.
Question

How exercise I find the perimeter with difficult shapes?

It can help to pause difficult shapes up into simpler shapes. Use area formulas for these simpler shapes to assist you notice all the side lengths of the complex shape.
Question

Tin I figure out the perimeter of an odd shape if I know its area?

No, the "oddness" of the shape makes it incommunicable to know the perimeter without more than data.
Question

The perimeter of a rectangle is 40cm & its breadth is 4cm less than the length. How exercise I find the length & breadth of this rectangle?

Permit L be the length. And then (L - 4) is the breadth. The perimeter is twice the length plus twice the breadth: ii (Fifty) + ii (L - four) = twoscore. Solve for L. The latitude will be 4 less than L.
Question

How to find an expression for the perimeter of a rectangle with a given expanse (trinomial 6x^ii+17x+12 format)?

To detect the perimeter of a rectangle with a trinomial equation as the area, you'll demand to factor this equation to get the sides. Once you've factored the equation, you lot tin and then add the sides to detect the perimeter.
Question

A rectangle has a ratio of three:ii. The area is 294 foursquare meters. What is the perimeter?

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Community Answer

A = 294 m^ii = 3x*2x = 6x^2 for some ten So x = 7m Perimeter= 2(3x + 2x), then plugging in the now known value x=7m yields P = 70m
Question

How practise I detect the perimeter of a rectangle if I accept the surface area, x squared - 81, and that's it?

If you assume that the length and width are both 9, yous could easily find the perimeter. However, you can't really assume the length and width are each ix, so you don't actually have enough information to calculate the perimeter.
Question

Can I find the perimeter if I don't know the length of the sides?

No, if you don't know any of the sides, you can't find the perimeter.
Question

What is the perimeter of a rectangle that has one of the sides vii m in length and the expanse is 651 m squared?

Split the surface area by the length. That gives you the width. Detect the perimeter past adding twice the length to twice the width.
Question

How exercise I observe the full square area if one rectangle is 32 sq surface area and one is 48 sq area?

Add 32 and 48.

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Commodity Summary X

To find the perimeter of a rectangle, use the formula P = ii × (l + w). Get-go, discover the length and width of the rectangle, and place them in the "l" and "w" variables in the equation. And so, add these measurements together. For example, for a rectangle with a length of fourteen cm and a width of 8 cm, you would add them to get 22 cm. Multiply the sum of the numbers by ii to get the perimeter, which in this case would be 44 cm. Exist sure to label your answer with the proper units! If you demand to detect the perimeter of a rectangle if you just know the area and the length of one side, continue reading the article!

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