Eric Nicholas K's answer to Lee's Secondary 3 E Maths Singapore question.

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Eric Nicholas K
Eric Nicholas K's answer
5997 answers (Tutor Details)
Good afternoon!

I have used a higher level approach to verify that the area of the shaded region is indeed 25 cm2, but this method is not to be used at the Secondary 3 level.

The proper way to go at the Secondary 3 level is still to consider the area of a segment within a sector.

I would expect this question to be approximately 4 marks long in an O Level examination paper, the break-down of which is 1 mark for finding the radius, 2 marks for finding the area of the segment and 1 mark for finding the total area of the shaded regions.