Here's why:

* Centimeter (cm): One centimeter is equal to one-hundredth of a meter (1/100 meter).

* Decimeter (dm): One decimeter is equal to one-tenth of a meter (1/10 meter).

Since 1/10 is larger than 1/100, a decimeter is bigger than a centimeter.

Think of it this way:

* 1 meter = 10 decimeters

* 1 meter = 100 centimeters

Therefore, 1 decimeter = 10 centimeters.