The investigation begins by looking at the area of three segments related to a quadratic. The investigation begins with a practical investigation using measurement of lengths and angles. The ratio of length of side to sine of the opposite angle is calculated.
There then follows work on two proofs of the sine rule. The first uses right angled triangles and the sine ratio. The second method uses a circumscribed circle with lines running from each vertex to the centre of the circle. The sine ratio is used and the result appears with a little further effort.
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