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PSLE 2021 · Paper 1 · Q7 Measurement & Geometry · Geometry (properties of shapes) 1 mark · mcq difficulty 1 of 5

PSLE 2021 Paper 1, Question 7: Geometry (properties of shapes)

The answer

Option (4), radius \(OE\), diameter \(FC\)

PSLE 2021 Paper 1 Question 7 · Verified worked solution by the Genius Plus Academy teaching team

What this question tests

This is Question 7 of the PSLE 2021 Paper 1 Mathematics paper. It tests geometry (properties of shapes), in the Measurement & Geometry strand. It is worth 1 mark. Open your copy of the paper at this question, then follow our full worked solution below.

Step-by-step solution

A radius joins the centre \(O\) to the circle (\(AO\), \(OE\), \(OC\), \(OF\) are all radii). A diameter passes through the centre with both ends on the circle: \(AE\) and \(CF\) are diameters (\(AOE\), \(COF\) straight lines). \(BD\) does not pass through \(O\). Only option (4) pairs a radius with a diameter correctly.

Answer: Option (4), radius \(OE\), diameter \(FC\)

Same structure, different costume

A question is hard because of its structure, not its story.

Change egg tarts to badges, a tank to two tanks, a ring of card to a folded sheet, and a child sees a brand new problem. The lock underneath is the same, and so is the key. Once a student can name the structure, a whole row of questions that look different start to open the same way.

It is also where marks really leak. Across fourteen years of papers, the marks lost in PSLE math leak at the reading far more than at the arithmetic, which is exactly why recognising the structure fixes them. We call this Lock and Key: name the lock, then the key follows.

See what the paper rewards → The hardest questions, shown working →

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