Chapter 5.3, Problem 25WE

To determine

To Find: One significant digit estimate of each of the following.

Answer to Problem 25WE

  $\frac{478\times 0.230}{0.0281\times 32.4}=100$

Explanation of Solution

Given information:

  $\frac{478\times 0.230}{0.0281\times 32.4}$

Concept:

There are three rules on determining how many significant figures are in a number.

They are

1.Non-zero digits are always Significant.

2.Any zeros between two significant digits are Significant.

3.A final zero or trailing zeros in the decimal portion ONLY are Significant.

  $\frac{478\times 0.230}{0.0281\times 32.4}$

The following rule applies for Multiplication and Division:

The LEAST number of significant figures in any number of the problem determines the number of Significant figures in the answer.

Using Above rule

We get

  $\begin{array}{l}\Rightarrow \frac{478\times 0.230}{0.0281\times 32.4}=\frac{1.10\times {10}^2}{0.910}\\ \Rightarrow \frac{478\times 0.230}{0.0281\times 32.4}=121\end{array}$

But we need only one Significant figure.

Therefore,

  $\Rightarrow \frac{478\times 0.230}{0.0281\times 32.4}=100$