Which of the following end with digit `1` ? `123^2,\ 77^2,\ 82^2,\ 161^2,\ 109^2`

Explanation

The squares of those numbers end in 1 which ends with either `1` or `9`.
`therefore 161^2`and `109^2` end with `1`.
`123^2=15129`
`77^2=5929`
`82^2=6724`
`161^2=25921`
`109^2=11881`