Question

A toy maker wants to re-create the Wright Brothers 1903 airplane. The actual plane was 21 feet long. The toy maker wants to use a scale model of 3 feet = 2 inches. How long will the replica plane be?

Answer 1

Answer:

$x = 14ft$

Step-by-step explanation:

Given

$Actual\ Length = 21ft$

Model:

$3\ ft = 2\ in$

Required

Determine the length of the replica

Represent the model as a ratio:

$Ratio = 3\ in:2\ ft$

Convert to fraction

$Ratio = \frac{3\ in}{2\ ft}$

Represent the actual lengths as a ratio

$Ratio = 21\ ft : x$

Where x is the length of the replica

Convert to fraction

$Ratio = \frac{21\ in}{x}$

Equate both ratios (because they are in proportion)

$\frac{3\ in}{2\ ft} = \frac{21\ in}{x}$

$\frac{3}{2\ ft} = \frac{21}{x}$

Cross Multiply:

$3 * x = 21 * 2\ ft$

$3x = 42\ ft$

Solve for x

$x = \frac{42ft}{3}$

$x = 14ft$

Hence, the length of the replica is 14ft