This data set has 5 observations.

     id    x1    x2
  <int> <dbl> <dbl>
1     1 -1.29  0.56
2     2  0.92 -0.40 
3     3  0.61 -0.59
4     4 -0.77 -0.29
5     5  2.12 -0.14

The following is the interpoint distance matrix between the 5 observations.

    1   2   3   4
2 2.6            
3 3.0 1.1        
4 3.2 2.6 1.7    
5 5.3 3.2 2.5 3.1

Observations 2 and 3 would be joined at the first step in hierarchical clustering, at a distance of 1.1. If observation 4 is then joined at the next step, using complete linkage, what would be the distance reported between cluster (2,3) and observation 4?