To find the diver's elevation when he is \(\frac{2}{3}\) of the way down to the treasure at a depth of 97.2 feet, we can calculate how deep the diver is when he has descended that fraction of the total depth.
First, we calculate how deep the diver is when he has descended \(\frac{2}{3}\) of the way down to 97.2 feet:
\[ \text{Depth descended} = 97.2 \text{ ft} \times \frac{2}{3} = 64.8 \text{ ft} \]
Since the diver is below the surface, we express this as a negative elevation:
\[ \text{Elevation} = -64.8 \text{ ft} \]
Thus, the diver's elevation when he is \(\frac{2}{3}\) of the way down is −64.8 ft.