Ask Experts Questions for FREE Help !
Ask
    Yusf's Avatar
    Yusf Posts: 198, Reputation: 3
    Junior Member
     
    #1

    Dec 14, 2013, 07:01 PM
    Math are getting harder. Can anyone give me a theory?
    Hello! Can anyone give me a theory that relates 3 angles of a triangle with a side?
    Wondergirl's Avatar
    Wondergirl Posts: 39,354, Reputation: 5431
    Jobs & Parenting Expert
     
    #2

    Dec 14, 2013, 07:02 PM
    a formula?
    Yusf's Avatar
    Yusf Posts: 198, Reputation: 3
    Junior Member
     
    #3

    Dec 14, 2013, 07:05 PM
    Yes. That's all I need.
    Wondergirl's Avatar
    Wondergirl Posts: 39,354, Reputation: 5431
    Jobs & Parenting Expert
     
    #4

    Dec 14, 2013, 07:07 PM
    If you know three angles, that won't help you figure out the length of a side. Do you know at least one side?
    Yusf's Avatar
    Yusf Posts: 198, Reputation: 3
    Junior Member
     
    #5

    Dec 14, 2013, 07:18 PM
    The question is like this.
    Assume a pole AB with Point C and D on 2 sides of it. If they are joined with A and B, We get 2 right angled triangles, ACB and ADB. Joining C and D gives right angled Triangle BCD at the base. Given that CD=200, angle ACB=15° and angle ADB=25° find the height of AB.
    Wondergirl's Avatar
    Wondergirl Posts: 39,354, Reputation: 5431
    Jobs & Parenting Expert
     
    #6

    Dec 14, 2013, 07:36 PM
    Are you taking trig?

    Did you draw a picture?
    Yusf's Avatar
    Yusf Posts: 198, Reputation: 3
    Junior Member
     
    #7

    Dec 14, 2013, 10:03 PM
    Yes its trig. I can draw a picture but how can I upload it here?
    Wondergirl's Avatar
    Wondergirl Posts: 39,354, Reputation: 5431
    Jobs & Parenting Expert
     
    #8

    Dec 14, 2013, 11:12 PM
    Quote Originally Posted by Yusf View Post
    Yes its trig. I can draw a picture but how can I upload it here?
    Does anything on this page help?

    Solving Triangles
    ebaines's Avatar
    ebaines Posts: 12,131, Reputation: 1307
    Expert
     
    #9

    Dec 16, 2013, 05:55 AM
    I am unable to follow your description of the problem (I have no idea what you mean by "Assume a pole AB with Point C and D on 2 sides of it"). It would really help if you could post a figure. Nevertheless, since you have one length given, have the various angles and want to find the length of another side of one of the triangles, you should be able to use the Law of Sines - for any triangle with side lengths A, B and C and angles a, b, and c:



    I'm guessing that from the figure you should be able to relate the 200' length of CD to the length of one of the sides of the triangle ABC or ABD. in order to determine length AB.
    Yusf's Avatar
    Yusf Posts: 198, Reputation: 3
    Junior Member
     
    #10

    Dec 17, 2013, 10:57 PM
    No. The I know the theories but can't use them as two measurements are not given. I tried The site wondergirl suggested Let me try to explain. For this example, names I use may be differrent from the ones I used earlier. Assume you drew a triangle BCD on the floor . CD is towards you and B is away from you. You insert a pole in B and tie rope from top of the pole A to C and A to D. Now we get triangle ACB on left and ADB on right and Bcd on bottom. This is the figure. Here angle CBD is 90° angle ACB is 15° and angle ADB is 25°.Line Cd is 200. Now I need the length of the pole.
    ebaines's Avatar
    ebaines Posts: 12,131, Reputation: 1307
    Expert
     
    #11

    Dec 18, 2013, 07:57 AM
    The height of the pole AB is equal to the length of BC times tan(15), and it's also equal to length BD times tan(25). Hence length BC= BD x tan(25)/tan(15). Now we can use Pythagoras on triangle BCD: BD^2 +BC^2 = 200^2, and since BC = BD x tan(25)/(tan15) this becomes 200^2 = (BD)^2 (1+ tan^2(25)/tan^2(15)). You can now solve for BD, and finally determine AB using length BD x tan (25).
    Yusf's Avatar
    Yusf Posts: 198, Reputation: 3
    Junior Member
     
    #12

    Dec 18, 2013, 10:41 PM
    Hey! The answer is 46.47. It EXACTLY matches with the answer of the book. Thanks a lot to Ebaines and Wonder girl for helping me.

Not your question? Ask your question View similar questions

 

Question Tools Search this Question
Search this Question:

Advanced Search


Check out some similar questions!

Give me the answer to math word problem [ 2 Answers ]

IT REquires 15 gallons of mulch to cover 5 floerbeds .how many are needed for7?

Free math word problem and it give me the answer [ 1 Answers ]

The u.s. senate has 100 members. After a certain election, there were 18 more democrats than republicans, with no other parties represented. How many members of each party were there in the senate?


View more questions Search