The length of a rectangle is 3 centimeters less than twice its width. The perimeter of the rectangle is 48 cm. What are the dimensions of the rectangle?

length = 14 cm; width = 10 cm

length = 12 cm; width = 12 cm

length = 15 cm; width = 9 cm

length = 11 cm; width = 7 cm

1 answer

To find the dimensions of the rectangle, let's denote the width as \( w \) centimeters. According to the problem, the length \( l \) can be expressed as:

\[ l = 2w - 3 \]

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

\[ P = 2l + 2w \]

We know the perimeter is 48 cm, so we can set up the equation:

\[ 2l + 2w = 48 \]

Substituting the expression for \( l \):

\[ 2(2w - 3) + 2w = 48 \]

Now, let's simplify the equation:

\[ 4w - 6 + 2w = 48 \]

Combine like terms:

\[ 6w - 6 = 48 \]

Now, add 6 to both sides:

\[ 6w = 54 \]

Dividing both sides by 6 gives:

\[ w = 9 \]

Now substitute back to find the length:

\[ l = 2(9) - 3 = 18 - 3 = 15 \]

So, the dimensions of the rectangle are:

  • Length = 15 cm
  • Width = 9 cm

From your provided options, the solution corresponds to:

length = 15 cm; width = 9 cm.