Cube metal sheeting

We have a cube measuring side a = 540 mm. However, it is made of 25 mm thick sheet metal. How much do I need to sheet the cubes inside and the bottom? The lid is not required.

Final Answer:

S =  13525 cm²

Step-by-step explanation:

$$\begin{gathered} a=540\text{mm} \\ h=25\text{mm} \\ {S}_1=(a-2\cdot h{)}^2=(540-2\cdot 25{)}^2=240100{\text{mm}}^2 \\ {S}_2=(a-h)\cdot a=(540-25)\cdot 540=278100{\text{mm}}^2 \\ {S}_3=S_1+4\cdot S_2=240100+4\cdot 278100=1352500{\text{mm}}^2 \\ S=S_3/100=1352500/100=13525{\text{cm}}^2 \end{gathered}$$

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