mathematics question.

[polarmystery]

I'm studying to take the FE exam in the fall and in my study book I'm reviewing trigonometry and identities. For some of the problems, it shows a angle representation I've never seen used before. What does it mean when an angle has an apostrophe with it?

Ex:

36 o 24 '

the o being the degree symbol. The book says 57 o 28 ' is equal to 57.467 o but how do I figure that out? I can't find anything on the net. Thanks.

 

[geno]

Minutes, as in a fraction of a degree.

EDIT, I'm pretty sure that's it. 28/60 = .467

Here's some more info

 

[polarmystery]

yeah that looks like that's it. So weird I don't remember using minutes in college for angles

 

[Soccer55]

The measurement is represented in degrees minutes seconds format. The ' symbol stands for minute(s) and there is another symbol '' that stands for second(s).

1 minute = 1/60 degree
1 second = 1/60 minute

So 57 o 28 ' = 57 + 28/60 = 57.467 (after rounding the decimal to 3 places)

Hope this helps

 

[polarmystery]

Originally posted by: Soccer55
The measurement is represented in degrees minutes seconds format. The ' symbol stands for minute(s) and there is another symbol '' that stands for second(s).

1 minute = 1/60 degree
1 second = 1/60 minute

So 57 o 28 ' = 57 + 28/60 = 57.467 (after rounding the decimal to 3 places)

Hope this helps

Yes it helps. Thank you. My question is why would you want to use that format? I've never used that format...ever. It doesn't even make sense to me.

 

[geno]

Originally posted by: polarmystery

Originally posted by: Soccer55
The measurement is represented in degrees minutes seconds format. The ' symbol stands for minute(s) and there is another symbol '' that stands for second(s).

1 minute = 1/60 degree
1 second = 1/60 minute

So 57 o 28 ' = 57 + 28/60 = 57.467 (after rounding the decimal to 3 places)

Hope this helps

Yes it helps. Thank you. My question is why would you want to use that format? I've never used that format...ever. It doesn't even make sense to me.

It's just the way it works *shrug* I've never seen degrees given as decimals or fractions. Minutes / seconds is the standard and I'm not sure why

 

[rgwalt]

Originally posted by: polarmystery

Originally posted by: Soccer55
The measurement is represented in degrees minutes seconds format. The ' symbol stands for minute(s) and there is another symbol '' that stands for second(s).

1 minute = 1/60 degree
1 second = 1/60 minute

So 57 o 28 ' = 57 + 28/60 = 57.467 (after rounding the decimal to 3 places)

Hope this helps

Yes it helps. Thank you. My question is why would you want to use that format? I've never used that format...ever. It doesn't even make sense to me.

Maps... latitude and longitude are represented in degrees, minutes, seconds.

 

[dullard]

Originally posted by: rgwalt
Maps... latitude and longitude are represented in degrees, minutes, seconds.

Exactly. That is the way it was done for centuries (when math on a calculator wasn't possible). The standard was never changed.

The key is that 60 is a wonderful number. Time, angles, maps, and other items frequently used 60. Why? Since it is easy to do math in your head with 60. What is half an hour? 60/2 = 30. What is a third of an angle? 60/3 = 20. A quarter? 60/4 = 15. A fifth? 60/5 = 12. Just about any commonly used division is easy to do with the number 60. Usually no decimals to worry about, usually no weird fractions. True, you can't easilly divide 60 by 17, but really, how often do you need to do that?

Oh and if you ever need to type anything for your homework, the degree symbol is this: ° . You type it by pressing and holding 'ALT' then start making a circle on the number pad by typing 248. Unfortunately, you don't complete the circle though by typing ALT-2486, as you get this crazy symbol: ¦ . So that isn't a perfect trick, but it is still helpful to remember.

 

[polarmystery]

Originally posted by: dullard

Originally posted by: rgwalt
Maps... latitude and longitude are represented in degrees, minutes, seconds.

Exactly. That is the way it was done for centuries (when math on a calculator wasn't possible). The standard was never changed.

The key is that 60 is a wonderful number. Time, angles, maps, and other items frequently used 60. Why? Since it is easy to do math in your head with 60. What is half an hour? 60/2 = 30. What is a third of an angle? 60/3 = 20. A quarter? 60/4 = 15. A fifth? 60/5 = 12. Just about any commonly used division is easy to do with the number 60. Usually no decimals to worry about, usually no weird fractions. True, you can't easilly divide 60 by 17, but really, how often do you need to do that?

Oh and if you ever need to type anything for your homework, the degree symbol is this: ° . You type it by pressing and holding 'ALT' then start making a circle on the number pad by typing 248. Unfortunately, you don't complete the circle though by typing ALT-2486, as you get this crazy symbol: ¦ . So that isn't a perfect trick, but it is still helpful to remember.

Sweet thanks!

This is more like work work, as I'm out of school and I study before I start working in my cube. Thanks for all the responses

 

[Paperdoc]

Yeah, the degrees / minutes / seconds system was devised a few centuries ago as part of sea navigation, and well before decimal systems became well established. They borrowed from the familiar system that says there are 60 minutes in an hour, and 60 seconds in a minute, to make it easy to remember I think. If you work it out, at the equator, 1 second of angle around the earth's surface comes to about 102 feet certainly a fine enough unit of resolution for mariners of the time.

 

[sao123]

Originally posted by: polarmystery
yeah that looks like that's it. So weird I don't remember using minutes in college for angles

DMS = degrees minutes seconds?

 

[polarmystery]

Originally posted by: sao123

Originally posted by: polarmystery
yeah that looks like that's it. So weird I don't remember using minutes in college for angles

DMS = degrees minutes seconds?

Nope. In EE, we just used radians mostly. When doing electromagnetics it was always radians and in Cal I,II,III, and Diff-Eq it was either degrees or radians. Never took a class with DMS.