meters to decimeters is meters times 10 there's also the King
Henry Chart to help you remember the units (King-Kilo Henry-Hecta
Died-Deka By-Base Drinking-Deci Chocolate-Centi Milk-Mili)

1 meter is 10 decimeters. Then, 9.1 meters is 91 decimeters. To show that, multiply 10 by 9.1 to get 91 decimeters. Formally, 9.1 meters * 10 decimeters / meters = 91 decimeters