Copier paper

A standard package of printer and copier paper is labeled 80 g/m², which means that one square meter of such paper weighs 80 g. How much does one sheet of A4 size (dimensions 210 × 297 mm) weigh? The result is rounded to whole grams.

Correct answer:

x =  5 g

Step-by-step explanation:

$$\begin{gathered} \sigma =80{\text{g/m}}^2 \\ a=210\text{mm}\to \text{m}=210:1000\text{m}=0.21\text{m} \\ b=297\text{mm}\to \text{m}=297:1000\text{m}=0.297\text{m} \\ S=a\cdot b=0.21\cdot 0.297\doteq 0.0624{\text{m}}^2 \\ x=\sigma \cdot S=80\cdot 0.0624=5\text{g} \end{gathered}$$

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