Welcome Paul,

You are looking for this rule:

**TDA Rules for 2017**

*Rule #47 Raise Amounts*

Part A: A raise must be at least equal to the largest prior bet or raise of the current betting round.

Your scenario is also covered further in:

**Illustrations Addendum for 2017 Rules**

* Rule 47: Raise Amounts. “The largest prior bet or raise of the current betting round”.*

**Example 2:** NLHE, Blinds 50-100. Pre-flop A is under the gun and goes all-in for a total of 150 (an increase in the bet of 50). So, we have a 100 blind bet and an all-in wager that increases the total by 50. Which is larger? The 100 is still the “largest bet or raise of the current round”, so if B wants to re-raise he must raise at least 100 for a total of 250.

So, that rule covers the requirement for raising. However, nothing forces the other players to raise. As Boris said, they can call the 3500.

If you have an iPhone, you can find these rules using the search engine the I built into the FREE TDA RULES app. See the link below.