The answer
\(x = 144\)
O-Level E-Math 2015 Paper 1 Question 16 · Verified worked solution by the Genius Plus Academy teaching team
What this question tests
This is Question 16 of the O-Level E-Math 2015 Paper 1. It tests interior angle sum of a polygon, in the Angles & polygons area. It is worth 3 marks. It is a worded / diagram-based question, so open your Ten-Year Series (TYS) or the official paper at this question, then follow our full worked solution below.
The interior angles of a hexagon sum to \((6 - 2) \times 180^{\circ} = 720^{\circ}\). Three angles are \(96^{\circ}\) each and the remaining three are equal (each \(x^{\circ}\)): \[3 \times 96 + 3x = 720 \Rightarrow 288 + 3x = 720 \Rightarrow 3x = 432 \Rightarrow x = 144.\]
Answer: \(x = 144\)
Same structure, different numbers
Swap the constants, dress a quadratic as a length, hide a derivative inside an integral, and a student sees a brand new problem. The structure underneath is the same, and so is the method. Once a student can name the structure, a whole row of questions that look different start to open the same way.
That is where marks really leak: in choosing the method, not in the algebra that follows. We call it Lock and Key, name the lock, then the key follows.
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Genius Plus Academy · O-Level & IP Mathematics
Our O-Level E-Math tuition trains the same recognise-the-structure method these worked solutions show, taught by a team that has marked these papers for years. It runs within our weekly Secondary Math programme, Sec 1 to 4 and IP.
It is a interior angle sum of a polygon question from Angles & polygons, worth 3 marks.
Yes. IP (Integrated Programme) schools teach the same O-Level Mathematics content; they just sequence it differently and set their own internal exams, so these worked solutions apply to IP students too.
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