Given:
F varies inversely with d²
So,
[tex]\begin{gathered} F\propto\frac{1}{d^2} \\ \\ F=\frac{k}{d^2} \end{gathered}[/tex]
Where (k) is the proportionality constant
We will find the value of (k) using the given condition
When F=21, d= 7
Substitute with (F) and (d):
[tex]\begin{gathered} 21=\frac{k}{7^2} \\ k=21\cdot7^2=21\cdot49=1029 \end{gathered}[/tex]
So, the answer will be:
The general formula to describe the variation is:
[tex]F=\frac{1029}{d^2}[/tex]
