I hope I understood the question correctly

Technically we don't

*need* a steal success rate of 48%. We only need that if we want to open raise any two and still auto-profit. So let's assume that's indeed what we're going for.

If so, you're right, we need a success rate of 2500/(2500+2625) = ~49%

Therefore, you indeed take 0.49^(1/3) = 0.79 = 79%, indicating you need them to fold 79% of the time on average.

The required fold frequency changes exponentially as we have more players behind us that need to fold, not linearly. That's the reason we take the cubed root. If it was just one player, we would just need him to fold 49% of the time. Against two players, we would take the square root again because we have to consider the second player. Same applies to the scenario here where we need 3 players to fold. And if we would have to make 7 players to fold we would take 0.49^(1/7).

Hope that makes sense