60 (number) geometry, it is the number of seconds in a minute, and the number of minutes in a degree. In normal space, the three interior angles of an equilateral triangle each measure 60 degrees, adding up to 180 degrees. Because it is divisible by the sum of its digits in base 10, it is a Harshad number. A number system with base 60 is called sexagesimal (the original meaning of "sexagesimal" is sixtieth). It is the smallest positive integer that is written with only the smallest and the largest digit of base 2 (binary), base 3 (ternary) and base 4 (quaternary).
Triangle β is the interior angle at "B", formula_28 is the interior angle at "C" and "c" is the line AB). Furthermore, since sin α = sin ("π" − α) = sin (β + formula_28), and similarly for the other two angles: "Knowing AAS": and analogously if the known side is "a" or "c". "Knowing ASA": and analogously if the known side is "b" or "c". The shape of the triangle is determined by the lengths of the sides. Therefore, the area can also be derived from the lengths of the sides. By Heron's formula: where formula_34 is the semiperimeter, or