The estimated value can be given by 21.76
To solve this expression, let's just:
[tex]\\\large \sf 102.3 \div 4.7 = 21.7659574468\\[/tex]
We can make the approximation to the first two numbers after the point, thus having the result
[tex]\red{\boxed{\large \sf \approx 21.76}}[/tex]
So, the answer will be 21.76