Step-by-step explanation:
A consensus is gained when a decision is made. I believe that a decision can be something which can turn out to be beneficial as well as unfavorable, but when a decision is made, the people involved in taking that decision reaches a consensus which trigger them to take that decision. So when people reach at a point where everyone is having a similar thought, they actually reach at a consensus and then they take decision regarding any issue. So in my opinion and what i believe, a Consensus is gained when a decision is made.