To find the total thickness of the two pieces of metal when stacked on top of each other, we need to add the two measurements together. The thicknesses are:
- Dr. Calvin's measurement: \(0.00064\) meters
- Dr. Amos's measurement: \(2.5 \times 10^{-5}\) meters
First, we will convert \(0.00064\) meters into scientific notation to make it easier to add the two measurements: \[ 0.00064 = 6.4 \times 10^{-4} \text{ meters} \]
Now we have:
- \(6.4 \times 10^{-4}\) meters (from Dr. Calvin)
- \(2.5 \times 10^{-5}\) meters (from Dr. Amos)
Next, we need to express \(2.5 \times 10^{-5}\) in terms of \(10^{-4}\) so we can add it to \(6.4 \times 10^{-4}\): \[ 2.5 \times 10^{-5} = 0.25 \times 10^{-4} \text{ meters} \]
Now we can add the two measurements: \[ 6.4 \times 10^{-4} + 0.25 \times 10^{-4} = (6.4 + 0.25) \times 10^{-4} = 6.65 \times 10^{-4} \text{ meters} \]
Thus, the total thickness of the two pieces of metal when stacked together is: \[ 6.65 \times 10^{-4} \text{ meters} \]
So, filling in the blank in your question, the answer is: \[ \text{6.65} \] Finally, the entire answer is \( \text{6.65} \times 10^{-4} \text{ meters} \).