Answer: The required value of x is 4.
Step-by-step explanation: We are given to solve the following equation for the value of x :
[tex]3:12=x:16~~~~~~~~~~~~~~~~~~~~~~~~~~~~~(i)[/tex]
We know that
[tex]a:b=\dfrac{a}{b}.[/tex]
So, from equation (i), we get
[tex]3:12=x:16\\\\\\\Rightarrow \dfrac{3}{12}=\dfrac{x}{16}\\\\\\\Rightarrow \dfrac{1}{4}=\dfrac{x}{16}\\\\\\\Rightarrow x=\dfrac{16}{4}\\\\\Rightarrow x=4.[/tex]
Thus, the required value of x is 4.
