Answer:
[tex]0.28\ \text{m}^2[/tex]
Step-by-step explanation:
[tex]4\ \text{cm}=0.2\ \text{m}[/tex]
[tex]1\ \text{cm}=\dfrac{0.2}{4}=0.05\ \text{m}[/tex]
[tex]28\ \text{cm}=28\times 0.05=1.4\ \text{m}[/tex]
The height of the layer is 0.2 m and the length is 1.4 m
Area is given by
[tex]0.2\times 1.4=0.28\ \text{m}^2[/tex]
Area of the actual quartz layer section is [tex]0.28\ \text{m}^2[/tex].