i want to extract every 3rd number ( 42.034 , 41.630 , 40.158 as so on ) from the file
see example-

```
42.034  13.749  28.463  41.630  12.627  28.412  40.158  12.173  30.831  26.823
12.596  32.191  26.366  13.332  32.938  25.289  12.810  32.419  23.949  13.329

```

Any suggestions using perl script ?

Thanks,
dac