Things that I find tricky (2)

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Rule 3

Opposite angles in a cyclic quadrilateral add up to 180 degrees

image: circle with a quadrilateral shape inside: top corner: A, right: B, bottom: C, left: D. (http://www.bbc.co.uk/schools/gcsebitesize/maths/images/figure_38.gif)B+D=180 degrees

                                                         A+C=180 degrees: A+B+C+D=180 degrees.

Rule 4

image: circle with triangular shape inside: top corner: P, bottom right: B, straight through: O to A on the bottom left. (http://www.bbc.co.uk/schools/gcsebitesize/maths/images/figure_36.gif)Angle at the centre is twice the angle at the circumference - AOB = 2APB.

Rule 5

(http://www.bbc.co.uk/schools/gcsebitesize/maths/images/ma_angles_amb0.gif)OM cuts…

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Nathan

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A+B+C+D should equal 360 degrees, (2 x 180)