Solve for X: Rectangle Perimeter 18 with Side Lengths 5x and 10x-8

Question

The shape below is composed of three rectangles.

Calculate x given that the perimeter of rectangle GCHF is 18.

AAABBBCCCGGGFFFHHHDDDEEE10x-83+x5x

Video Solution

Solution Steps

00:06 Let's find the value of X.
00:15 In rectangle G F C H, the opposite sides are equal.
00:26 In rectangle A B G C, the opposite sides are equal too.
00:36 The perimeter of a rectangle is the total of all its sides.
00:43 Now, substitute the known values, and solve the equation for X.
01:13 Next, collect like terms together.
01:31 Then, isolate the X to get its value.
01:38 And that's how we solve for X!

Step-by-Step Solution

To solve this problem, we'll follow these steps:

  • Step 1: Write the expression for the perimeter of rectangle GCHF using the given variables.
  • Step 2: Set up the equation by equating the expression to 18.
  • Step 3: Solve the equation for x x .

Let's work through each step:

Step 1: The perimeter of rectangle GCHF is given by the formula:

Perimeter=2×(length)+2×(width) \text{Perimeter} = 2 \times (\text{length}) + 2 \times (\text{width})

According to the diagram, the dimensions of the rectangle GCHF are:

- GH = 3+x 3 + x (length),

- GF = 5x 5x (width).

Thus, the perimeter formula becomes:

2×(3+x)+2×(5x) 2 \times (3 + x) + 2 \times (5x)

Step 2: Set the equation equal to the given perimeter, 18:

2(3+x)+2(5x)=18 2(3 + x) + 2(5x) = 18

Step 3: Simplify and solve for x x :

Distribute the 2:

6+2x+10x=18 6 + 2x + 10x = 18

Combine like terms:

6+12x=18 6 + 12x = 18

Subtract 6 from both sides:

12x=12 12x = 12

Divide both sides by 12 to isolate x x :

x=1 x = 1

Therefore, the solution to the problem is x=1 x = 1 .

Answer

1