Question

John found that the perimeter of a square is 2x+30 ft. If the perimeter's length is 128
ft 128 ft what is the value of x?
x=____ft

Answer 1

The perimeter \( P \) of a square can be calculated using the formula:

\[
P = 4s
\]

where \( s \) is the length of one side of the square. According to the problem, John found that the perimeter can also be expressed as \( P = 2x + 30 \) ft. We are given that the perimeter is also equal to 128 ft.

To find the value of \( x \), we can set the two expressions for the perimeter equal to each other:

\[
2x + 30 = 128
\]

Now, we will solve for \( x \):

1. Subtract 30 from both sides:

\[
2x = 128 - 30
\]
\[
2x = 98
\]

2. Now, divide both sides by 2:

\[
x = \frac{98}{2}
\]
\[
x = 49
\]

Thus, the value of \( x \) is

\[
\boxed{49 \text{ ft}}
\]