Math Problem Statement

By how much would the perimeter of a square be decreased if its area is halved?

Solution

To solve this problem, let's first analyze the relationship between the area and the perimeter of a square.

Step 1: Determine the side length of the original square.

Let the side length of the original square be ss. The area of the square is given by:

Area=s2\text{Area} = s^2

Step 2: Determine the new side length after halving the area.

If the area is halved, the new area is s22\frac{s^2}{2}. Let the new side length be ss'. Then:

(s)2=s22(s')^2 = \frac{s^2}{2}

Taking the square root of both sides:

s=s2s' = \frac{s}{\sqrt{2}}

Step 3: Calculate the perimeters.

  • The perimeter of the original square is 4s4s.
  • The perimeter of the new square is 4s=4×s2=4s2=22s4s' = 4 \times \frac{s}{\sqrt{2}} = \frac{4s}{\sqrt{2}} = 2\sqrt{2}s.

Step 4: Determine the decrease in perimeter.

The decrease in the perimeter is the difference between the original and the new perimeters:

Decrease in perimeter=4s22s=s(422)\text{Decrease in perimeter} = 4s - 2\sqrt{2}s = s(4 - 2\sqrt{2})

Step 5: Simplify the expression.

The numerical value of 4224 - 2\sqrt{2} is approximately:

42242×1.41442.8281.1724 - 2\sqrt{2} \approx 4 - 2 \times 1.414 \approx 4 - 2.828 \approx 1.172

So, the perimeter decreases by approximately 1.172×s1.172 \times s.

Conclusion:

The perimeter of the square would be decreased by approximately s(422)s(4 - 2\sqrt{2}), or roughly 1.172×s1.172 \times s, where ss is the original side length of the square.

Would you like more details or have any questions?


  1. How does the area of a square relate to its perimeter?
  2. What is the exact value of 2\sqrt{2}?
  3. How does changing the side length affect the perimeter of a square?
  4. What is the relationship between area and side length in any polygon?
  5. How would the answer change if the area was tripled instead of halved?

Tip: When dealing with square roots, it's often helpful to approximate their values to understand the magnitude of the result.

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Math Problem Analysis

Mathematical Concepts

Geometry
Square properties

Formulas

Area of a square: s^2
Perimeter of a square: 4s

Theorems

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Suitable Grade Level

Grades 7-9