Crossword puzzle clue "3 75 feet once"

Roughly 15 feet by 6 feet by 5 feet, for the Focus?

5 feet to 10 feet and 60 meters to 120 meters

Animal with four toes on its front feet and three toes on its back feet

Once, once more and yet once more

He once had feet of Clay

3.75 feet, once

At once, once

Danish astronomer who was exhumed twice, once to examine the causes of death and once to identify the material of his artificial nose