Cube wall

The surface of the first cube wall is 64 m². The second cube area is 40% of the surface of the first cube. Find the length of the edge of the second cube (x).

Correct answer:

x =  2.0656 m

Step-by-step explanation:

$$\begin{gathered} S_1=64{\text{m}}^2 \\ q=40\%=\frac{40}{100}=\frac{2}{5}=0.4 \\ {S}_2=q\cdot S_1=0.4\cdot 64=\frac{128}{5}=25.6{\text{m}}^2 \\ {S}_2=6x^2 \\ x=\sqrt{S_2/6}=\sqrt{25.6/6}=2.0656\text{m} \end{gathered}$$

Try another example