fraction multiplication with square root as the numerator

Question

Can anyone explain how did the author arrived at the answer?

I can do multiplication of fractions like 1/2 * 1/3 etc... but I stumbled at this question

$$3/5 * \sqrt(3)/2 = 3/10 \sqrt3$$

Answer 1

$$\frac{3}{5}\cdot\frac{\sqrt{3}}{2}=\frac{3}{10}\cdot\sqrt{3}\Longleftrightarrow$$ $$\frac{3\cdot\sqrt{3}}{5\cdot2}=\frac{3}{10}\cdot\sqrt{3}\Longleftrightarrow$$ $$\frac{3\cdot\sqrt{3}}{10}=\frac{3}{10}\cdot\sqrt{3}\Longleftrightarrow$$ $$\frac{3\cdot\sqrt{3}}{10}=\frac{3\cdot\sqrt{3}}{10}$$

Because $2\cdot5=10$.