Math Problem Statement

The length of a rectangle is twice its width. The perimeter of the rectangle is 24 inches. Write a system of equations in 2 variables. Use substitution to solve the problem.

a. Equation 1:

         Equation 2:



b. What is the area of the rectangle?

Solution

a. Writing the system of equations

Let:

  • LL be the length of the rectangle.
  • WW be the width of the rectangle.

From the problem, we know the following:

  1. The length of the rectangle is twice the width:
    L=2W(Equation 1)L = 2W \quad \text{(Equation 1)}

  2. The perimeter of the rectangle is 24 inches. The formula for the perimeter of a rectangle is:
    P=2L+2WP = 2L + 2W Substituting the given perimeter: 2L+2W=24(Equation 2)2L + 2W = 24 \quad \text{(Equation 2)}

b. Solving the system of equations

Step 1: Substitution

  • From Equation 1, L=2WL = 2W. Substitute this expression for LL in Equation 2:

2(2W)+2W=242(2W) + 2W = 24

Step 2: Simplify and solve for WW: 4W+2W=244W + 2W = 24 6W=246W = 24 W=246=4W = \frac{24}{6} = 4

Step 3: Find LL: Now that W=4W = 4, substitute this into Equation 1 to find LL: L=2W=2(4)=8L = 2W = 2(4) = 8

c. Finding the area of the rectangle

The area AA of a rectangle is given by: A=L×WA = L \times W Substitute L=8L = 8 and W=4W = 4: A=8×4=32square inchesA = 8 \times 4 = 32 \, \text{square inches}

Final Answer:

The area of the rectangle is 32 square inches.


Would you like more details or have any questions about this solution?

Here are 5 follow-up questions:

  1. How do you derive the formula for the perimeter of a rectangle?
  2. Can this method be applied to solve for other shapes with different perimeter conditions?
  3. What happens if the perimeter changes to 30 inches instead of 24?
  4. How would the system of equations change if the length was three times the width?
  5. Can you graph the equations to visualize the solution?

Tip: In substitution problems, always start by solving one equation for a single variable, then substitute it into the other equation to reduce the system to one variable.

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Math Problem Analysis

Mathematical Concepts

Algebra
Linear Equations
Geometry

Formulas

Perimeter of a rectangle: P = 2L + 2W
Area of a rectangle: A = L × W
Substitution method

Theorems

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Suitable Grade Level

Grades 6-8