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Unformatted text preview: Decimal Degrees ↔ Minutes & Seconds
Much the same as an hour, a degree may also be broken up into minutes and seconds. That is, 60 minutes
( 60′ ) equals 1 degree, and 60 seconds ( 60′′ ) equals 1 minute.
Examples: 18°25′ + 15°52′ = 33°77′ = 34°17′ Note that we subtracted 60′ from 77′ and added 1° to 33° . 18°25′ − 15°52′ = 17°85′ − 15°52′ = 2°33′ Note that we “borrowed” 1° from 18° and added
60′ to 25′ .
Converting between degrees/minutes/seconds and decimal degrees should be mastered as early in this
course as possible. This can be done by hand or by using the TI83/4.
The symbols for degrees and minutes are options #1 and #2 under the angle menu. The symbol for
seconds is found by pressing alpha +.
1) Decimal degrees → degrees, minutes and seconds.
a) By hand: 35.125° → 35° + .125(60′ ) → 35° + 7.5′ → 35°7′ + .5(60′′) → 35°7′30′′ .
b) Using the TI83/4: Enter 35.125° , then press 2nd angle #4 enter. The calculator should now read the
correct result, 35°7′30′′ .
For Practice: Convert 83.6572° to degrees/minutes/seconds, accurate to the nearest second. Try this by
hand, and check your answer with your calculator. 2) Minutes and seconds → decimal degrees 7 30 ° + ° → 35.125° . This works because each minute 60 3600 a) By hand: 35°7′30′′ → 35° + represents 1/60 of a degree, and each second represents 1/3600 of a degree.
b) Using the TI83/4: Enter 35°7′30′′ . Once the angle has been entered, simply press enter and the
calculator will automatically convert to decimals. 35°7′30′′ enter → 35.125° .
For Practice: Convert 27°18′25′′ to decimal degrees, with threedecimalplace accuracy. Try this by
hand, and check your answer with your calculator. ...
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 Fall '09
 COHEN
 Trigonometry

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