An airplane ticket has an area of 286 square centimeters. Its perimeter is 70 centimeters. What are the dimensions of the ticket?

centimeters by
centimeters

1 answer

Let the length of the airplane ticket be \( l \) cm and the width be \( w \) cm. We have two pieces of information:

  1. The area of the ticket: \[ lw = 286 \]
  2. The perimeter of the ticket: \[ 2l + 2w = 70 \]

We can simplify the perimeter equation: \[ l + w = 35 \]

Now we have the following system of equations:

  1. \( lw = 286 \)
  2. \( l + w = 35 \)

From the second equation, we can express \( w \) in terms of \( l \): \[ w = 35 - l \]

Now we can substitute this expression for \( w \) into the first equation: \[ l(35 - l) = 286 \] Expanding this gives: \[ 35l - l^2 = 286 \]

Rearranging this into standard quadratic form, we get: \[ l^2 - 35l + 286 = 0 \]

Now we can use the quadratic formula to solve for \( l \): \[ l = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \] where \( a = 1 \), \( b = -35 \), and \( c = 286 \).

Calculating the discriminant: \[ b^2 - 4ac = (-35)^2 - 4 \cdot 1 \cdot 286 = 1225 - 1144 = 81 \]

Now substituting these values into the quadratic formula: \[ l = \frac{35 \pm \sqrt{81}}{2 \cdot 1} = \frac{35 \pm 9}{2} \]

Calculating the two possible values for \( l \):

  1. \( l = \frac{35 + 9}{2} = \frac{44}{2} = 22 \)
  2. \( l = \frac{35 - 9}{2} = \frac{26}{2} = 13 \)

Thus, we have two possible dimensions:

  • If \( l = 22 \), then \( w = 35 - 22 = 13 \)
  • If \( l = 13 \), then \( w = 35 - 13 = 22 \)

Therefore, the dimensions of the ticket are \( 22 \) centimeters by \( 13 \) centimeters.

Final answer: \[ 22 \text{ centimeters by } 13 \text{ centimeters} \]