A.
The perimeter of the pentagon is the sum of the 5 sides of the figure
the sum of the five sides = x + x + x+ 3x +3x (centimeter)
=> 9x
we are also told that the perimeter is 54 centimeter
=> 9x = 54
B.
to solve the equation 9x = 54
divide both sides by the coefficient of x
[tex]\begin{gathered} \frac{9x}{9}=\frac{54}{9}\text{ } \\ x\text{ = 6} \end{gathered}[/tex]C. to get the length of each sides, substitue the value for x=6 into the sides so that we will have
6, 6, 6, 3(6), 3(6)
=> 6, 6, 6, 18,18 centimeters