Question

Question #15f43

Answer 1

`5`

Explanation:

The first thing to look for when trying to figure out how many significant figures you have in a measurement are non-zero digits.

Non-zero digits are always significant, regardless if they are added before or after the decimal place. In your case, you have three non-zero digits

`color(black)(color(red)(7)0. color(red)(8)0color(red)(4) ->` three non-zero digits

so you know for a fact that the measurement has at least three sig figs.

The first zero

`7color(blue)(0).804`

is significant because it follows a non-zero digit, i.e. `7`, and it is being followed by a non-zero digit, i.e. `8`. Zeros that are "sandwiched" between two non-zero digits are always significant.

Notice that the second zero

`70.8color(blue)(0)4`

is also sandwiched between two non-zero digits. This zero follows `8` and it is being followed by `4`, so you know for a fact that this zero is significant.

Therefore, you can say that the measurement given to has `5` significant figures

`color(black)(color(red)(7)color(blue)(0). color(red)(8)color(blue)(0)color(red)(4) -> {("three non-zero digits"), ("two sandwiched zeros") :}`