Answer:
We do not use a smaller figure scale to measure larger figures, it would be lengthy and would alter the number of significant figures in our measurement.
Step-by-step explanation:
An astronomical unit (AU) is a unit quantized based on the distance from the Sun to the Earth. It is helpful to determine relatively how far are the other planets from the Sun, compared to Earth. It would be lengthy to express that in kilometers, hence we would require a bigger unit to make calculations much more simple and easy to comprehend.