Question

A tire impression left in the mud at a crime scene was 8.7 inches wide. How many centimeters is that?

Answer 1

The answer is `22.098` `cm`.

Use the multiply by 1 method to ensure you have the correct ratio:

`8.7 Inch *(2.54 cm)/(1 Inch)=22.098` `cm`

We have the inches cancelling out and `cm` remaining in the numerator, so the units are correct.

This is multiplying by 1 because we are multiplying by 2 things that are equal, that is, `2.54` `cm=1` inch. You need to put the units that you want into the numerator and the units you want to cancel out in the denominator.