Question

express as a co-function of a complementary angle: sin 15°20'
ans: 75° 40'
I understand that you have to do: 90-15°=75°
but how do I get the "40' "??

Answer 1

One degree is 60 minutes (60')
One minute is 60 seconds (60")

Another way of measuring angles was invented in Babylon (which is at present located in northern Iraq) more than 3,500 years ago. They first divided the circumference of a circle into 6 parts (this is easy with a compass). Then they divided each part into 60 smaller parts, which we now call degrees (they used base 60). When smaller units were needed, they kept dividing each bigger unit by 60. So now we have 1 degree = 60 minutes ("minute" means "small" in Latin), and 1 minute = 60 seconds ("second small parts"). In this way, the Babylonians bypassed the need for finding the ratio circumference/radius.

The Babylonians' way of measuring angles was so successful that we still use it. It even survived the introduction of the metric system, where ratios of units are powers of 10 and not 60.
http://tinyurl.com/cx6f4zx

Answer 2

the problem @Directrix the 2 angles sum to 91 degrees.

Answer 3

Thanks @campbell_st I totally missed that and interpreted the question as being about the reasoning for 60 minutes in a degree.

Answer 4

@Ikushinkan
Did you see @campbell_st post on this thread? Your angles should be 15° 20'
and 74° 40'

Answer 5

all co-function means is that

\[\sin(x) = \cos(90 - x)\]

Answer 6

so I'd say a typo...

Answer 7

Yes I did! Thanks for your help, however sadly I was looking at the wrong problem :( This one wasn't assigned :/ So sorry. I really need to rest I guess! But thank you so much for your time! I feel terrible...

Answer 8

its ok... at least you got some help with the question/\.