- The Conversion
To combine these two separate fractions, we have to find a common denominator. To avoid involving decimal places by dividing the 30/3600 by 60 to make the common denominator 60, we make the common denominator 3600 by multiplying 30/60 by 60. This now gives us 25º + 1800/3600 + 27/3600, or 25º + 1827/3600.
The 1827/3600 can be reduced by dividing each number with a common denominator, which in this case is 9. The new fraction is then 203/400, giving us 25º + 204/400, or 25º 203/400.
To express this as a decimal version, the 203 is divided by 400, giving 0.5075, which makes the angle 26.5075º.
If the original angle had been 25º 30 minutes 0 seconds, for instance, the fraction would have been 25 1800/3600º, which could have been reduced to 25 1/2º or 25.5º.
An original angle of 25º 30 minutes 57 seconds would equal 25 1857/3600º. As there is no common denominator for 1857 and 3600, it can not be reduced. Expressed in decimals, the angle would be 25.5158333333º.
This example was given to show that the actual figures ultimately determine how far a fraction can be reduced.