Raji draws a square with a side length of x + 5 cm. Ava draws a regular hexagon with a side length of x - 1 cm. The two figures have the same perimeter. Write an equation that allows you to solve for x. What is the value of x?

A. 18
B. 12
C. 26
D. 13

1 answer

To find the value of \( x \), we first need to express the perimeters of both shapes in terms of \( x \).

  1. Perimeter of the square: The side length of the square is \( x + 5 \) cm. The perimeter \( P_{\text{square}} \) of a square is given by the formula: \[ P_{\text{square}} = 4 \times \text{side length} = 4(x + 5) \] Expanding this, we get: \[ P_{\text{square}} = 4x + 20 \]

  2. Perimeter of the regular hexagon: The side length of the hexagon is \( x - 1 \) cm. The perimeter \( P_{\text{hexagon}} \) of a regular hexagon is: \[ P_{\text{hexagon}} = 6 \times \text{side length} = 6(x - 1) \] Expanding this gives: \[ P_{\text{hexagon}} = 6x - 6 \]

  3. Setting the perimeters equal: Since the problem states that the two figures have the same perimeter, we set the equations for their perimeters equal to each other: \[ 4x + 20 = 6x - 6 \]

  4. Solving for \( x \): We can solve this equation step by step: \[ 4x + 20 = 6x - 6 \] Subtract \( 4x \) from both sides: \[ 20 = 2x - 6 \] Add \( 6 \) to both sides: \[ 26 = 2x \] Finally, divide both sides by \( 2 \): \[ x = 13 \]

So, the value of \( x \) is \( \boxed{13} \).