### Home > MC1 > Chapter 7 > Lesson 7.2.4 > Problem7-83

7-83.

Consider the diagram of three pieces of lumber shown below.

$\underline{{4}\text{ meters}} \quad \underline{\ \ \ {x}\ \ \ } \quad \underline{\ \ \ {x}\ \ \ }$

1. If $x = 6$ meters, how long are all three pieces of lumber laid end to end?

Since $x = 6$ meters, the three pieces of lumber now look like this:

$\underline{{4}\text{ meters}} \quad \underline{{6}\text{ meters}} \quad \underline{{6}\text{ meters}}$

Can you find the total length of the lumber pieces?

1. If the total length of all three pieces laid end to end is $20$ meters, what is the value of $x$?

Using the diagram above, can you write an expression to represent the pieces of lumber?

If $4 + x + x = 20,$ why must $x + x = 16$?

Can you find the value of $x$?