Mr Reed is drawing a blueprint of a rectangular patio . the width of the patio is 40 3/4 feet shorter than twice its length . the perimeter of the patio is 86 1/2 feet . what is the length of the patio

1 answer

Let the length of the patio be \( L \) feet. According to the problem, the width \( W \) of the patio is given by:

\[ W = 2L - 40.75 \]

The perimeter \( P \) of the rectangle is given by the formula:

\[ P = 2L + 2W \]

We know that the perimeter is \( 86.5 \) feet, so we can set up the equation:

\[ 2L + 2W = 86.5 \]

Substituting the expression for \( W \):

\[ 2L + 2(2L - 40.75) = 86.5 \]

Now simplify the equation:

\[ 2L + 4L - 81.5 = 86.5 \]

Combine like terms:

\[ 6L - 81.5 = 86.5 \]

Now isolate \( 6L \):

\[ 6L = 86.5 + 81.5 \]

\[ 6L = 168 \]

Now divide both sides by 6 to find \( L \):

\[ L = \frac{168}{6} = 28 \]

So, the length of the patio is \( \boxed{28} \) feet.

To confirm, let's calculate the width using the expression for \( W \):

\[ W = 2(28) - 40.75 = 56 - 40.75 = 15.25 \]

Now, check the perimeter:

\[ P = 2L + 2W = 2(28) + 2(15.25) = 56 + 30.5 = 86.5 \]

This confirms that our calculations are correct. The length of the patio is indeed \( \boxed{28} \) feet.