What is the circular mil of a wire with a diameter of 7/8 inch?

To determine the circular mils of a wire, the formula used is based on the diameter in inches. The circular mil is calculated using the equation:

[

\text{Circular mils} = \left(\text{Diameter in inches}\right)^2 \times 1,273,000

]

For a wire with a diameter of 7/8 inch, first convert that diameter to decimal form:

[

7/8 = 0.875 \text{ inches}

]

Next, square the diameter:

[

0.875^2 = 0.765625

]

Since the question is about calculating the circular mils, it is essential to understand that one circular mil is defined as the area of a circle with a diameter of one mil (0.001 inches). Hence, the conversion involves multiplying by the constant factor of 1,000,000 (since there are 1,000,000 circular mils in a square inch).

Thus, the calculation becomes:

[

\text{Circular mils} = 0.765625 \times 1,000,000 = 765,625 \text{ cm}

]

This calculation aligns with the answer choice selected, confirming