Question

Suppose you are 5 feet 2 inches tall. Give your height in meters and centimeters. For example, "9'2" = 2.8 meters = 2 meters and 80 centimeters."?

Answer 1

That is basically correct, except the cm value should be 79, not 80.

Explanation:

This is a conversion that just depends on the accuracy of the standard. As a basis we can use `1.00 "inch" = 2.54cm`, `1.00 "foot" = 12.0 "inches"` and `1.00m = 100cm`

For the example, 9'2" can be converted first into inches:
`9 xx 12 + 2 = 110"inches"`.
This can be converted into cm:
`110 xx 2.54 = 279.4cm`

This can then be converted into meters and cm:
`2m and 79cm`, or the `2m and 80cm` expressed as only one significant digit. In this case the original data (110 inches) had two significant digits (or possibly, 3!), so the final answer should as well.

This highlights the introduction of error based on WHEN you do any rounding, and why. Rounding from 279cm to 280cm, or 2.8m is incorrect unless you want to express your result in meters only. If you are going to report the cm value, the correct calculated one is 79, not 80.