• # question_answer 1)                 In a model of a ship, the mast is 9 cm high, while the mast of the actual ship is 12 m high. If the length of the ship is 28 m, how long is the model ship?

Let the length of the model ship be $x\,\,cm$. We form a table as shown below:
 Actual ship Model Length of the ship 28 m $x$ Height of the mast 12 m 9 cm
More the length of the ship, more would be the length of its mast. Hence, this is a case of direct proportion. That is,                 $\frac{{{x}_{1}}}{{{y}_{1}}}=\frac{{{x}_{2}}}{{{y}_{2}}}$ $\Rightarrow$               $\frac{28}{12}\,=\frac{x}{9}$ $\Rightarrow$               $12x=28\times 9$ $\Rightarrow$               $x=\frac{28\times 9}{12}$ $\Rightarrow$               $x=21$ Hence, the length of the model ship is 21 cm.