The circumference 3

The circumference of a cylindrical water tank is 62.8m. When it is 4/5 full of water, it holds 125.6 hectoliters. Find the depth of the tank.

Correct answer:

h =  0.05 m

Step-by-step explanation:

$$\begin{gathered} o=62.8\text{m} \\ {V}_1=125.6\text{hl}\to {\text{m}}^3=125.6:10{\text{m}}^3=12.56{\text{m}}^3 \\ \frac{4}{5}\cdot V=V_1 \\ \frac{4}{5}\cdot V=12.56 \\ 4/5\cdot V=12.56 \\ 4V=62.8 \\ V=\frac{62.8}{4}=15.7 \\ V=\frac{157}{10}=15.7 \\ o=2\pi \cdot r \\ r=o/(2\pi )=62.8/(2\cdot 3.1416)\doteq 9.9949\text{m} \\ {S}_1=\pi \cdot r^2=3.1416\cdot 9.9949^2\doteq 313.8408{\text{m}}^2 \\ V=S_1\cdot h \\ h=V/S_1=15.7/313.8408=0.05\text{m} \end{gathered}$$

Try another example