To find the combined water capacity of the two towers, we can simply add the two amounts together:
- The first tower holds \( 7.35 \times 10^5 \) gallons.
- The second tower holds \( 9.78 \times 10^5 \) gallons.
Now, we can add them together:
\[ 7.35 \times 10^5 + 9.78 \times 10^5 = (7.35 + 9.78) \times 10^5 = 17.13 \times 10^5 \]
Next, we need to express this in proper scientific notation. The coefficient \( 17.13 \) can be written as \( 1.713 \) by moving the decimal one place to the left, which increases the exponent by 1:
\[ 17.13 \times 10^5 = 1.713 \times 10^6 \]
Thus, the combined water capacity in scientific notation is:
\[ \boxed{1.713 \times 10^6} \]
So the correct response from the options provided is:
1.713×106
1 point 7 1 3 times 10 to the 6th power