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Can you answer this question please

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Flamed-Ghoust:
http://papers.xtremepapers.com/CIE/Cambridge%20IGCSE/Mathematics%20(0580)/0580_s03_qp_2.pdf

Question 12 please

NotAbod:
(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

Flamed-Ghoust:

--- Quote from: NotAbod on November 03, 2013, 04:43:04 pm ---(a)
angle ABC is 90 degrees.
90 + 2p + 3p = 180
p = (180-90)/5
p = 18


--- End quote ---

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.

NotAbod:
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

Flamed-Ghoust:
Thank you so much,  ^-^ +rep mate

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