Numbers 60 was first used by the Sumerians, so they count in base 60 or also called sexagesimal.
Sexagesimal is a mathematical calculation based on 60.
The reason why the number 60 is the number used is the smallest number that can be shared by the first six digits are: 1,2,3,4,5,6
Then how history says that 1 minute = 60 seconds?
In 1956, the International Committee for Weights and Measures (CIPM), under the command given by the General Conference on Weights and Measures (CGPM) to 10 in 1954, describes the second in a period of rotation of the earth around the sun, because at that time had realized that earth's rotation on its axis is not uniform enough to be used as the standard time.
Earth movement was described in Newcomb's Tables of the Sun (solar List Newcomb), which provides a formula for the motion of the sun at the epoch in 1900 based on astronomical observations made ​​during the 18th century and into the 19. Thus the second is defined as 1/31.556.925, 9747, part of the solar year in the date 0 January 1900 at 12 time ephemeris.
This definition was ratified by the General Conference on Weights and Measures to 11 in 1960. Reference to the year 1900 does not mean this is the mean solar day contains 86,400 seconds.
Rather it is the tropical year which contains 31,556,925.9747 second of Ephemeris Time. Time Ephemeris (Ephemeris Time - ET) has been defined as a measure of time which gives the position of celestial objects visible in accordance with Newton's theory of dynamic movement.
With the establishment of an atomic clock, then determined using atomic clocks as the basis for the definition of seconds, no longer with the rotation of the earth. From the work of several years, two astronomers in the United States Naval Observatory (USNO) and two astronomer at the National Physical Laboratory (Teddington, England) determine the relationship of the hyperfine transition frequency of the cesium atom and the ephemeris second.
By using common-view measurement method based on signals received from radio stations WWV, they determined that the orbital motion of the moon around the earth, from which the sun's apparent motion can be guessed, in the atomic clock time unit. As a result, in 1967, the General Conference on Weights and Measures defined the second of atomic time in the International System of Units (SI) as the duration of 9,192,631,770 periods of radiation with respect to the transition between two hyperfine levels of the ground state of cesium-133 atom .
Ground state is defined in the lack of circumstances (zero) magnetic field. Seconds are defined the same as ephemeris seconds. Second definition is refined in subsequent meetings BIPM.
And as we know that the calculation for 1 hour = 60 minutes, it's all because of the use of mathematical calculations sexagesimal.