Question

A ratio of equivalent values used to express the same quantity in different units

Answer 1

Conversion factor.

Hopefully this helps ! :)

Answer 2

Answer: There is something called the conversion factor.

For example, 1km is 1000 meters, so the conversion factor that goes from km to meters, is : $\frac{1000m}{km}$

And if you have a quantity expressed in kilometers, and want to write it in meters, you multiply it for the conversion factor.