To find the depth of Lake Segundo, which is said to be 56% as deep as Lake Profondo, we start by calculating 56% of Lake Profondo's depth of 84 feet.
\[ \text{Depth of Lake Segundo} = 0.56 \times 84 \text{ feet} \] \[ \text{Depth of Lake Segundo} = 47.04 \text{ feet} \]
Now, we need to determine the elevation at the bottom of Lake Segundo, knowing that the elevation is below sea level. Since elevations below sea level are expressed as negative numbers, we represent the depth as a negative value.
Thus, the elevation at the bottom of Lake Segundo is:
\[ \text{Elevation at the bottom of Lake Segundo} = -47.04 \text{ feet} \]
Therefore, the elevation at the bottom of Lake Segundo is \(-47.04\) feet.