SPM 2018 Add Maths Paper 1, Question 12Circular Measure

Solved on video in English and Bahasa Melayu · 4 marks · Form 5, Circular Measure · 5:26 video

The question

Diagram 5 shows a circle with centre O. PR and QR are tangents to the circle at points P and Q respectively. It is given that the length of minor arc PQ is 4 cm and OR = 5/α cm. Express in terms of α (a) the radius, r, of the circle, (b) the area, A, of the shaded region.

[4 marks]

SPM 2018 Add Maths Paper 1, Question 12: the question as drawn in Eduly's video5:26

Step 1

Angle POQ = α radians is the angle at the centre between the two radii OP and OQ, each of length r.

7 more steps, each with the reason for it, in the full solution

Final answer

(a) r = 4/α cm; (b) A = (12 − 8α)/α² cm²

Where students lose marks

Watch out: use the tangent-radius right angle for Pythagoras, subtract the sector from the kite (not the reverse), and keep the common denominator α².

Watch every step of this question solved on video (5:26), with the reason behind each step and a box that checks your own answer.

Start 7 days freeAlready a member? Watch it now

No card. Every past-year question on video, in English and BM.

All questions in SPM 2018 Paper 1

Circular Measure: lessons and every past-year question

Baca dalam Bahasa Melayu

More Circular Measure questions

Questions are re-typeset by Eduly for study and commentary. Eduly is not affiliated with Lembaga Peperiksaan Malaysia or the Ministry of Education.