Solve for X: Area vs. Perimeter in Two Altered Square Equations

Question

Given two squares, one side of the squares is larger by 2 than the other. The area of the large square is larger than the perimeter of the small square by 20

Find the length of the small square

X+2X+2X+2X+2X+2X+2XXXXXX

Video Solution

Solution Steps

00:00 Find X
00:03 Use the formula for calculating the area of a square (side squared)
00:11 Use the distributive property to expand the brackets
00:20 The perimeter of the square equals the sum of its sides
00:23 In a square all sides are equal
00:27 Substitute in the equation and solve for X
00:38 Simplify what we can
00:44 Isolate X
00:48 And this is the solution to the problem
00:51 X is positive because it represents a side length

Step-by-Step Solution

To find the length of the smaller square, we need to solve the equation derived from the problem statement:

  • Step 1: Write down the equation for the area of the larger square: (x+2)2(x + 2)^2.
  • Step 2: Write down the equation for the perimeter of the smaller square: 4x4x.
  • Step 3: Set up the equation as given: (x+2)2=4x+20(x + 2)^2 = 4x + 20.

Let's solve the equation:

Step 1: Expand (x+2)2(x + 2)^2:

(x+2)2=x2+4x+4(x + 2)^2 = x^2 + 4x + 4

Step 2: Rewrite the equation substituting the expanded form:

x2+4x+4=4x+20x^2 + 4x + 4 = 4x + 20

Step 3: Simplify by eliminating 4x4x from both sides:

x2+4=20x^2 + 4 = 20

Step 4: Subtract 4 from both sides:

x2=16x^2 = 16

Step 5: Take the square root of both sides:

x=4x = 4 or x=4x = -4

Since xx must be positive, we have:

x=4x = 4

Thus, the length of the side of the smaller square is 44.

Answer

4