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

00:13 Let's find the value of X. Are you ready?
00:17 First, we use the formula for the area of a square, which is side times side.
00:24 Next, let's expand those brackets using the distributive property. Take it step by step.
00:33 Remember, the perimeter of a square is the sum of all its sides.
00:38 In a square, all sides are equal. Keep that in mind!
00:43 Now, substitute the values into the equation and try to solve for X.
00:51 Let's simplify what we can. You're doing great!
00:57 Isolate X by rearranging the equation. Almost there!
01:02 And there you have it! That's the solution to the problem.
01:06 Remember, X is positive because it represents a length of a side.

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