A rectangular 4

A rectangular garden has a length of 57 m and a width of 42 m. Calculate how much m² will decrease the garden area if the ornamental fence width of 60 cm is planted inside its perimeter.

Correct answer:

S =  117.36 m²

Step-by-step explanation:

$$\begin{gathered} a=57\text{m} \\ b=42\text{m} \\ c=60\text{cm}\to \text{m}=60:100\text{m}=0.6\text{m} \\ {S}_1=a\cdot b=57\cdot 42=2394{\text{m}}^2 \\ {S}_2=(a-2\cdot c)\cdot (b-2\cdot c)=(57-2\cdot 0.6)\cdot (42-2\cdot 0.6)=\frac{56916}{25}=2276.64{\text{m}}^2 \\ S=S_1-S_2=2394-2276.64=117.36{\text{m}}^2 \end{gathered}$$

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