The area of a rectangle is given by the following formula:
A = w×l
Where w and l are the width and length of the rectangle. By replacing 3/4 for l and 1/5 for w, we get:
[tex]A=\frac{3}{4}\times\frac{1}{5}[/tex]In order to multiply fractions, we just have to multiply numerators and denominators, like this:
[tex]A=\frac{3\times1}{4\times5}=\frac{3}{20}[/tex]Then, the area of the given rectangle is 3/20 cm²