Question

A metric unit for mea surfing length that is equal to 10 meters is called a?

Answer 1

I think what you're looking for is a dekameter (decameter)

Just remember:
Kilo-1,000
Hecto-100
Deca-10
Unit-1
Deci-0.1
Centi-0.01
Milli--0.001

Answer 2

King (Kilo)
Henry (Hecto)
Died (Deca)
Unusually (Unit- meter, liter, gram)
Drinking (Deci)
Chocolate (Centi)
Milk (Milli)

The answer to ur question is Decameter cuz 10 meters=1 decameter