Chapter 5.7, Problem 30IP

To determine

To find: The width of the postcard.

Answer to Problem 30IP

The width of the postcard is $46\frac{2}{3}\text{in}$ .

Explanation of Solution

Given information:

A $14\text{in}$ wide by $20\text{in}$ long print of the Eiffel tower is also available as a postcard $6$ inches long.

Calculation:

The area of the rectangular region is,

  $\text{A}=\text{L}\times \text{B}$

Substitute $14$ for $\text{B}$ and $20$ for $\text{L}$ in the formula.

  $\begin{array}{c}\text{A}=\text{L}\times \text{B}\\ =20\text{in}\times 14\text{in}\\ =280{\text{in}}^2\end{array}$

So, the area of the long print of Eiffel tower is $280{\text{in}}^2$ .

To match the print with postcard area must be same for both.

Substitute $280$ for $\text{A}$ and $6$ for $\text{L}$ in the formula for area.

  $\begin{array}{c}280=\text{L}\times \text{B}\\ 280=6\text{in}\times \text{B}\\ \text{B}=\frac{280}{6}\\ \text{B}=46\frac{2}{3}\end{array}$

Therefore, the width of the postcard is $46\frac{2}{3}\text{in}$ .