Answer: The required simplified form of the given ratio is 3 : 4.
Step-by-step explanation: We are given to express the following ratio in simplest form :
\(R=21:28~~~~~~~~~~~~~~~~~~~~~~~~~~(i)\)
We will be using the following rule :
\(a:b=\dfrac{a}{b}.\)
From (i), we get
\(R=21:28=\dfrac{21}{28}=\dfrac{7\times3}{7\times4}=\dfra{3}{4}=3:4.\)
Thus, the required simplified form of the given ratio is 3 : 4.
