* Convert everything to the same units: There are 10 millimeters in 1 centimeter.

* Set up a proportion: Let 'x' represent the percentage we're looking for. We have:

8 mm / 10 mm = x / 100%

* Solve for x:

* Cross-multiply: 8 * 100 = 10 * x

* Simplify: 800 = 10x

* Divide both sides by 10: x = 80

Therefore, 8 millimeters is 80% of 1 centimeter.