A standard size pool cue is about 144 cm long. What is the length of a model of this pool cue with the scale factor 0.6?
So for this, set up a proportion.
$${\frac{{\mathtt{144}}}{{\mathtt{1}}}} = {\frac{{\mathtt{x}}}{{\mathtt{0.6}}}}$$
Cross-multiply to get the answer.
$${\mathtt{0.6}}{\mathtt{\,\times\,}}{\mathtt{144}} = {\mathtt{x}}$$
$${\mathtt{144}}{\mathtt{\,\times\,}}{\mathtt{0.6}} = {\mathtt{144}}{\mathtt{\,\times\,}}\left({\frac{{\mathtt{6}}}{{\mathtt{10}}}}\right)$$
Thus, the answer is 86.4