Looking at the given expression, the value of p is given by the value of f divided by 2:
[tex]p=\frac{f}{2}[/tex]
If the value of f is 12.9 cm, we have:
[tex]p=\frac{f}{2}=\frac{(12.9\text{ cm})}{2}=6.45\text{ cm}[/tex]
Therefore the answers are 12.9 and 6.45.
