Q&A for How to Find the Perimeter of a Rectangle

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  • Question
    How do I compute the missing side of a triangle?
    Taylor Klein
    Advanced Math Teacher
    Taylor Klein is an Advanced Math Teacher based in Philadelphia, Pennsylvania. She has worked in the education field for over 10 years, including eight years as a middle school Advanced Math Teacher. She has a master’s degree in Instructional Technology and Design and a master’s degree in Educational Leadership and Administration.
    Advanced Math Teacher
    Expert Answer
    When dealing with a rectangle, you can find the length of the missing side by utilizing division or by manipulating the equation through your understanding of literal equations. In the context of triangles, a similar principle applies. If you know the area and the lengths of two sides of a triangle, you can employ appropriate formulas, such as the formula for the area of a triangle. To solve for the length of the missing side, the Pythagorean theorem is commonly used for right-angled triangles, and trigonometric ratios can be employed for various types of triangles. It ultimately depends on the specifics of the triangle in question.
  • Question
    How can I find the side of a rectangle if perimeter is given?
    Donagan
    Top Answerer
    You can't. With any given perimeter, an infinite number of length-width combinations would be possible.
  • Question
    How do I find the perimeter with difficult shapes?
    Community Answer
    It can help to break difficult shapes up into simpler shapes. Use area formulas for these simpler shapes to help you find all the side lengths of the complex shape.
  • Question
    Can I figure out the perimeter of an odd shape if I know its area?
    Donagan
    Top Answerer
    No, the "oddness" of the shape makes it impossible to know the perimeter without more information.
  • Question
    The perimeter of a rectangle is 40cm & its breadth is 4cm less than the length. How do I find the length & breadth of this rectangle?
    Donagan
    Top Answerer
    Let L be the length. Then (L - 4) is the breadth. The perimeter is twice the length plus twice the breadth: 2 (L) + 2 (L - 4) = 40. Solve for L. The breadth will be 4 less than L.
  • Question
    How to find an expression for the perimeter of a rectangle with a given area (trinomial 6x^2+17x+12 format)?
    Community Answer
    To find the perimeter of a rectangle with a trinomial equation as the area, you'll need to factor this equation to get the sides. Once you've factored the equation, you can then add the sides to find the perimeter.
  • Question
    A rectangle has a ratio of 3:2. The area is 294 square meters. What is the perimeter?
    Orangejews
    Community Answer
    A = 294 m^2 = 3x*2x = 6x^2 for some x So x = 7m Perimeter= 2(3x + 2x), so plugging in the now known value x=7m yields P = 70m
  • Question
    How do I find the perimeter of a rectangle if I have the area, x squared - 81, and that's it?
    Donagan
    Top Answerer
    If you assume that the length and width are both 9, you could easily find the perimeter. However, you can't really assume the length and width are each 9, 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?
    Donagan
    Top Answerer
    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 7 m in length and the area is 651 m squared?
    Donagan
    Top Answerer
    Divide the area by the length. That gives you the width. Find the perimeter by adding twice the length to twice the width.
  • Question
    How do I find the total square area if one rectangle is 32 sq area and one is 48 sq area?
    Donagan
    Top Answerer
    Add 32 and 48.
  • Question
    If width = x and length = x + 40% and perimeter of the rectangle is 360 m, how do I find the value of x?
    Donagan
    Top Answerer
    The width is x, and the length is (x + 40%). (x + 40%) = (x + 0.4x) = 1.4x. The perimeter is twice the width plus twice the length, which is (2x) + 2(1.4x) = (2x) + (2.8x) = 4.8x.
  • Question
    What if the width is 840 m and the length is 48 m longer?
    Donagan
    Top Answerer
    Let w be the width. Then the length is (w + 48). The perimeter is twice the width plus twice the length, or 2w + 2(w+48) = 2w + (2w + 96) = 4w + 96 = 840. Then 4w = 744, and w = 186 m.
  • Question
    How can I find the perimeter of rectangle, if the width and diagonal is given?
    Donagan
    Top Answerer
    Use the Pythagorean theorem to find the length. (Square the diagonal, and from that subtract the square of the width. That gives you the square of the length, so find its square root.) Once you know the length, double it, and add twice the width. That's the perimeter.
  • Question
    How do I find the border of a square if I know its area?
    Donagan
    Top Answerer
    If you're asking about the perimeter of a square, first find the square root of its area. That gives you the length of any side. Multiply that length by 4 to get the perimeter.
  • Question
    How do I find the perimeter of a rectangle if I am only provided the area?
    Donagan
    Top Answerer
    It can't be done, because a rectangle with a given area could have several different length/width combinations (leading to different perimeters).
  • Question
    How do I find the perimeter if length is 40 cm and width is 5 cm? What is the height?
    Donagan
    Top Answerer
    The "height" of a rectangle is also referred to as it width. As shown above, a rectangle's perimeter is twice its length plus twice its width.
  • Question
    How do I find length and with if I only have perimeter and area?
    Iris8989
    Community Answer
    If it's a square, you could square root the area. The area of a square is equal to length * width. Since the sides are the same you can just square root the area to get the length and width of the square. If it's a rectangle, use equations to solve it. L (length) * W (width) = (insert the area). 2L + 2W = (insert the perimeter). Then test different lengths and widths that multiply to the area, and equal the perimeter when you apply the 2L + 2W perimeter formula.
  • Question
    How do I find the perimeter of rectangle when area and length is given, but breadth is not given?
    Donagan
    Top Answerer
    Divide the area by the length. That gives you the breadth (width). Add twice the breadth to twice the length to get the perimeter.
  • Question
    The perimeter of a rectangular sink is 21 inches. What is its width if its length is 3 inches greater than its width?
    Community Answer
    Let x be the width. Then (x + 3) is the length. So 21 = 2x + 2(x + 3) = 2x + 2x + 6 = 4x + 6. 21 = 4x + 6. Subtract 6 from both sides of the equation: 15 = 4x. Divide both sides by 4: x = 15/4 = 3 3/4 inches. That's the width. (To check the answer: the length is 3 3/4 + 3 = 6 3/4. Then the perimeter is 2(3¾) + 2(6¾) = 7½ + 13½ = 21.)
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