Video Transcript
Using a calculator, write 25
degrees, 30 minutes, and 45 seconds in degrees.
We recall that the single quotation
mark for the number in the question stands for minutes and the double quotation mark
stands for seconds. We also know that there are 60
minutes in one degree. In turn, a minute is made up of 60
seconds. We need to work out how we can use
this information to convert 25 degrees, 30 minutes, and 45 seconds into just
degrees. One way is to consider all three
parts separately. We know that we have 25 full
degrees. As one degree is equal to 60
minutes, one minute will be equal to one sixtieth of a degree. We can, therefore, convert 30
minutes into degrees by multiplying 30 by one sixtieth. This is the same as dividing 30 by
60.
In the same way, one second is
equal to one sixtieth of a minute. We can, therefore, convert 45
seconds into degrees by multiplying 45 by one sixtieth and then by one sixtieth
again. A quicker way to do this would be
to recognize that as 60 multiplied by 60 is 3600, then one second is equal to one
three thousand six hundredths of a degree. We can, therefore, convert 45
seconds into degrees by multiplying 45 by one over 3600. This is the same as 45 divided by
3600. 30 divided by 60 is equal to
0.5. 45 divided by 3600 is 0.0125. Adding these two answers together
with 25 gives us 25.5125. 25 degrees, 30 minutes, and 45
seconds is equal to 25.5125 degrees.
There is a quicker way of doing
this in one step on the calculator. This involves using the degrees,
minutes, and seconds button that can be found on the majority of scientific
calculators. We begin by inputting the number
25. We then press our button. We input 30 followed by the button
again. Finally, we input 45 and the button
a third time. When we press the equals button,
the number 25 degrees, 30 minutes, and 45 seconds will appear on our calculator
display. We then need to press the degrees,
minutes, and seconds button a final time, which will give us the answer 25.5125. This is the answer that we
calculated earlier in degrees.
