Test Index

JAMB Mathematics 2024 Paper

Question : 9

Total: 50

From the figure above, find the length of Chord PQ

Solution:

Concept:

The length of a chord in a circle is given by

2r\sin\left(\frac{\theta}{2}\right)

, where

r

is the radius and

\theta

is the angle subtended at the centre by the chord.

Explanation:

From the figure, the radius of the circle is

r = 9\text{ cm}

The angle subtended at the centre is

\theta = 60^\circ

Substitute into the chord length formula:

PQ = 2r\sin\left(\frac{\theta}{2}\right)

PQ = 2 \times 9 \times \sin\left(\frac{60^\circ}{2}\right)

PQ = 18 \times \sin 30^\circ

Since

\sin 30^\circ = \frac{1}{2}

PQ = 18 \times \frac{1}{2} = 9\text{ cm}

Answer:

9\text{ cm}

(Option D).

Go to Question:

Prev Question

Next Question