A worker is welding on structural steel near a gantry crane. They are anchored 1 foot below their D-ring using a 6 foot shock-absorbing lanyard.

A worker is welding on structural steel near a gantry crane. They are anchored 1 foot below their D-ring using a 6 foot shock-absorbing lanyard. How would I calculate the free-fall distance based upon the D-ring location? Please Show all calculations.