Answer:
4/r
Step-by-step explanation:
The side lengths s of an equilateral triangle inscribed in a circle of radius r will be ...
s = r√3
The perimeter of the triangle will be 3s.
The area of the triangle will be s^2·(√3)/4.
Then the ratio P/A is ...
P/A = (3s)/(s^2·(√3)/4) = (4√3)/s
Substituting the above expression for s, we have ...
P/A = 4√3/(r√3)
P/A = 4/r