Tennis polo
The sport is played on a grass field between 80 and 100 yards long and 50 to 65 yards wide. The goal area is a semicircular line with an 11-yard radius and the penalty mark at 13 yards from the goal. An experimental rule has a second semicircular line on the field with a 17-yard radius. Generally, a field for gridiron football or soccer can be used.
Hectometre
The hectometre (International spelling as used by the International Bureau of Weights and Measures; SI symbol: hm) or hectometer (American spelling) is an uncommonly used unit of length in the metric system, equal to one hundred metres. The word comes from a combination of "metre" and the SI prefix "hecto-", meaning "hundred". A soccer field is approximately 1 hectometre in length. The hectare (ha), a common metric unit for land area, is equal to one square hectometre (hm).