Block-shaped 44771

How much m² of paper do we save if we do not glue one-third of the total area of ​​the block-shaped billboard area with dimensions of 0.6 m, 0.7 m, and 1.4 m?

Correct answer:

x =  1.49 m²

Step-by-step explanation:

$$\begin{gathered} a=0.6\text{m} \\ b=0.7\text{m} \\ c=1.4\text{m} \\ S=2\cdot (a\cdot b+b\cdot c+c\cdot a)=2\cdot (0.6\cdot 0.7+0.7\cdot 1.4+1.4\cdot 0.6)=\frac{112}{25}=4.48{\text{m}}^2 \\ x=\frac{1}{3}\cdot S=\frac{1}{3}\cdot \frac{112}{25}=\frac{1\cdot 112}{3\cdot 25}=\frac{112}{75}=\frac{112}{75}{\text{m}}^2=1.49{\text{m}}^2 \end{gathered}$$

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