You measure the radius of a wheel........?

Question

to be 4.16cm. If you multiply by 2 to get the diameter, should you write the result as 8 cm or 8.32? Justify your answer.

Answer 1

The multiplication doesn't change the precision, since 2 is an exact value derived from the definition of radius and circumference. So I would write it as 8.32 cm.

In other words, we could have written the 2 as 2.0.