Cad iad méideanna spanner impiriúil?

An méid mar seo a leanas

: 1/4 orlach - 5/16 orlach - 3/8 orlach - 7/16 orlach - 1/2 orlach - 9/16 orlach - 5/8 orlach- 11/16 orlach - 3/4 orlach - 13/16 orlach - 7/8 orlach - 15/16 orlach