Square Nanometer [nm²]
A square nanometer (nm²) is a unit of area equal to a square with sides 1 nanometer long (1 nm = 1 billionth of a meter, or 10⁻⁹ m).
It’s used to measure extremely tiny areas, like the surface of molecules or nanomaterials.
1 nm² = 1 × 10⁻¹⁸ m².
Circular Inch
A circular inch is a unit of area used primarily in engineering and wire gauge measurements. It represents the area of a circle with a diameter of one inch.
Formula: Area = π × (radius)²
Since the radius is half an inch,
Area = π × (0.5 in)² = π × 0.25 in² ≈ 0.7854 square inches (in²).
Circular inches are often used to specify cross-sectional areas of wires or pipes.