A base-10 unit circle would be abhorrent. 1/2 of a circle is an important concept, but 1/5th and 1/10th of a circle are rarely used in geometry or trigonometry. Meanwhile, a right angle (1/4 of a circle) would require an ugly fraction, and the angle of an equilateral triangle (1/6th) would require a repeating decimal.
Think of 12-hour clocks and 360-degree circles as paper bags. When we’re fucking with angular concepts, you do not want to take those bags off Decimal’s head.
A base-10 unit circle would be abhorrent. 1/2 of a circle is an important concept, but 1/5th and 1/10th of a circle are rarely used in geometry or trigonometry. Meanwhile, a right angle (1/4 of a circle) would require an ugly fraction, and the angle of an equilateral triangle (1/6th) would require a repeating decimal.
Think of 12-hour clocks and 360-degree circles as paper bags. When we’re fucking with angular concepts, you do not want to take those bags off Decimal’s head.