7.) Eydy Neurons are cells in the nervous system that process and transmit information. An average neuron is about \( 5 \times 10^{-6} \) meter in diameter. A standard table tennis ball is 0.04 meter in diameter. About how many times as great is the diameter of a ball than a neuron?

**Step 1:** Write down the diameters of the neuron and the table tennis ball: - Neuron diameter: \( 5 \times 10^{-6} \) meter - Ball diameter: \( 0.04 \) meter **Step 2:** Set up the ratio of the ball's diameter to the neuron's diameter: \[ \text{Ratio} = \frac{0.04}{5 \times 10^{-6}} \] **Step 3:** Express \(0.04\) in scientific notation: \[ 0.04 = 4 \times 10^{-2} \] **Step 4:** Substitute the scientific notation into the ratio: \[ \text{Ratio} = \frac{4 \times 10^{-2}}{5 \times 10^{-6}} \] **Step 5:** Divide the constants and subtract the exponents: \[ \text{Ratio} = \frac{4}{5} \times 10^{-2 - (-6)} = \frac{4}{5} \times 10^4 \] **Step 6:** Simplify the constant: \[ \frac{4}{5} = 0.8 \] **Step 7:** Multiply: \[ 0.8 \times 10^4 = 8000 \] **Final Answer:** The table tennis ball's diameter is about \( 8000 \) times greater than the neuron's diameter.