Question

Find the third proportional to 1.6 and 2.4.

Answer 1

If $$x$$ is the third proportional to $$a$$ and $$b$$, then $$a : b :: b : x \Rightarrow x = \frac{b^2}{a}$$.

$$x = \frac{(2.4)^2}{1.6} = \frac{5.76}{1.6} = 3.6$$