Answer:
The lenght of the first piece is 6 feet.
The lenght of the second piece is 18 feet.
The lenght of the third piece is 30 feet.
Step-by-step explanation:
Let be:
[tex]x[/tex] the lenght of the first piece (in feet).
[tex]3x[/tex] the lenght of the second piece (in feet).
[tex]5x[/tex] the lenght of the third piece (in feet).
You know that the total lenght of the piece of siding is 54 feet. This means that:
[tex]x+3x+5x=54[/tex]
Having this expression, you can solve for "x":
[tex]9x=54\\\\x=\frac{54}{9}\\\\x=6[/tex]
Therefore, the lenght of the first piece is 6 feet.
Then:
[tex]3x=3(6)=18[/tex] (The lenght of the second piece is 18 feet)
[tex]5x=5(6)=30[/tex] (The lenght of the third piece is 30 feet)