The square centimeter (cm²) is a metric area unit equal to one ten-thousandth of a square meter, commonly used in medical reports, lab measurements, and small product specifications. Skin lesion sizes, fabric swatches, and circuit board components are often measured in square centimeters. One square centimeter equals exactly 0.155 square inches.

The acre is an imperial unit of area equal to 43,560 square feet or about 4,047 square meters, predominantly used in the United States, United Kingdom, and former British colonies for land measurement. Real estate listings, farmland boundaries, and suburban lot sizes in these regions are conventionally expressed in acres. One acre is roughly equivalent to 90% of a standard football pitch.