WAEC Mathematics 2012 Objective — Question 42

Question 42 of 50 from the West African Examinations Council (WAEC) Mathematics 2012 Objective paper, with the correct answer and a full explanation.

The diagram above is a circle of radius |OQ|=4cm. Line /TR/ is a tangent to the circle at R. If ∠TPO=120°, find /PQ/.

• A. 2.32cm
• B. 1.84cm
• C. 0.62cmCorrect
• D. 0.26cm

Explanation

Using sin60° = 4/|PO| (from the tangent-radius right angle and the given angle), |PO| is found, and |PQ| = |PO|−|OQ| ≈ 0.62cm.

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