Find the dimensions of a rectangle with a fixed area of 50 square units that min

Practice Questions

Q1
Find the dimensions of a rectangle with a fixed area of 50 square units that minimizes the perimeter. (2022) 2022
  1. 5, 10
  2. 7, 7.14
  3. 10, 5
  4. 8, 6.25

Questions & Step-by-Step Solutions

Find the dimensions of a rectangle with a fixed area of 50 square units that minimizes the perimeter. (2022) 2022
  • Step 1: Understand that we need to find the dimensions of a rectangle with an area of 50 square units.
  • Step 2: Recall that the area of a rectangle is calculated by multiplying its length (L) by its width (W): Area = L * W.
  • Step 3: Set up the equation for the area: L * W = 50.
  • Step 4: To minimize the perimeter, remember that the perimeter (P) of a rectangle is calculated as: P = 2L + 2W.
  • Step 5: Use the area equation to express W in terms of L: W = 50 / L.
  • Step 6: Substitute W in the perimeter equation: P = 2L + 2(50 / L).
  • Step 7: Simplify the perimeter equation: P = 2L + 100 / L.
  • Step 8: To find the minimum perimeter, take the derivative of P with respect to L and set it to zero: dP/dL = 2 - 100 / L^2 = 0.
  • Step 9: Solve for L: 2 = 100 / L^2, which gives L^2 = 50, so L = sqrt(50).
  • Step 10: Since W = 50 / L, substitute L back to find W: W = 50 / sqrt(50) = sqrt(50).
  • Step 11: Conclude that both dimensions (length and width) are equal, making the rectangle a square with side length of sqrt(50).
  • Step 12: Calculate the approximate value of sqrt(50): sqrt(50) ≈ 7.07.
  • Optimization – The problem involves finding the dimensions of a rectangle that minimize the perimeter while maintaining a fixed area.
  • Geometric Properties – Understanding the relationship between the area and perimeter of rectangles and squares.
  • Calculus (if applicable) – Potential use of derivatives to find minimum values, although not explicitly required in this solution.
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