Author Topic: Can you answer this question please  (Read 9834 times)

Offline Flamed-Ghoust

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Offline NotAbod

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Re: Can you answer this question please
« Reply #1 on: November 03, 2013, 04:43:04 pm »
(a)
angle ABC is 90 degrees.
90 + 2p + 3p = 180
p = (180-90)/5
p = 18

(b)
AEDC is a cyclic quadrilateral, therefore opposite angles = 180
Angle CAE + CDE = 180
q + 5q = 180
q = 180/6
q = 30

Offline Flamed-Ghoust

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Re: Can you answer this question please
« Reply #2 on: November 04, 2013, 10:50:30 am »
(a)
angle ABC is 90 degrees.
90 + 2p + 3p = 180
p = (180-90)/5
p = 18


Thank you very much NotAbod, but how do you know the third angle for part "a" is 90 degrees, it doesn't say so in the question. And a square is not drawn in the diagram that will prove that it is equal to 90 degrees.
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Offline NotAbod

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Re: Can you answer this question please
« Reply #3 on: November 04, 2013, 06:03:01 pm »
You must learn circle theorems.

ABC is a cyclic triangle. AOC is Diameter.
Let Angle ABC = x
then AOC is 2x.
AOC is diameter and its angle is 180

ABC x 2 = AOC
2x = 180
x = 180/2
x = 90

Take a look at this and learn them: http://www.mathsisfun.com/geometry/circle-theorems.html

Offline Flamed-Ghoust

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Re: Can you answer this question please
« Reply #4 on: November 06, 2013, 02:00:52 am »
Thank you so much,  ^-^ +rep mate
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Offline Flamed-Ghoust

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Re: Can you answer this question please
« Reply #5 on: November 06, 2013, 02:22:06 am »
Can you help me now with this question please.
I found the area but could not find the angle, so in the exam i wrote it 60 degrees even though i doubt it is. ;D :-*

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Offline Flamed-Ghoust

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Re: Can you answer this question please
« Reply #6 on: November 07, 2013, 07:21:18 am »
Come on i have my paper 4 today and i am not getting an answer yet????
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Offline NotAbod

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Re: Can you answer this question please
« Reply #7 on: November 07, 2013, 02:54:05 pm »
Have you tried SOH CAH TOA?
ie sin (x) = opposite/hypotenuse etc

Sorry for the late reply, really busy with my university.

Offline Flamed-Ghoust

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Re: Can you answer this question please
« Reply #8 on: November 08, 2013, 04:47:45 pm »
the triangle is not 90 degrees, so the SOH CAH TOA wont work... the sin rule also wont work cause i only have 1 angle and that angle is unknown, the cosine rule also wont work cause we only have one side and the other 2 are unknown, the biggest problem is that the intersection of AC isnt equal in size
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Offline astarmathsandphysics

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Re: Can you answer this question please
« Reply #9 on: November 08, 2013, 06:14:40 pm »
See attachment

Offline NotAbod

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Re: Can you answer this question please
« Reply #10 on: November 08, 2013, 07:28:34 pm »
the triangle is not 90 degrees, so the SOH CAH TOA wont work... the sin rule also wont work cause i only have 1 angle and that angle is unknown, the cosine rule also wont work cause we only have one side and the other 2 are unknown, the biggest problem is that the intersection of AC isnt equal in size

AXB is 90 Degrees and I assume you know XB and AC is given as 12cm
Use SOHCAHTOA to find angle ABX (which is 1/2 of ABC)
ABX x 2 = ABC

Offline Flamed-Ghoust

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Re: Can you answer this question please
« Reply #11 on: November 09, 2013, 06:31:14 am »
how is angle ABX half od angle ABC????
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Offline NotAbod

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Re: Can you answer this question please
« Reply #12 on: November 09, 2013, 08:13:56 pm »
It's a kite and that diagonal (DB) cut the smaller triangle (triangle ABC) into 2 equal halves therefore ABX x 2 = ABC

Offline Flamed-Ghoust

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Re: Can you answer this question please
« Reply #13 on: November 10, 2013, 06:36:23 am »
oh, so u basically mean make an imaginery line ??
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Offline NotAbod

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Re: Can you answer this question please
« Reply #14 on: November 11, 2013, 05:32:47 pm »
Yes and no.
Yes if it's not there.
No in this case because it's already there, line BD