WAEC - Mathematics (1994 - No. 27)
The angle subtended at the centre by a chord of a circle radius 6cm is 120°. Find the length of the chord.
3cm
6cm
\(4\sqrt{2}\) cm
\(3\sqrt{3}\) cm
\(6\sqrt{3}\) cm
説明
\(\frac{r}{6} = \sin 60 \)
\(r = 6 \sin 60\)
= \(6 \times \frac{\sqrt{3}}{2}\)
= \(3\sqrt{3}\)
Chord = 2r = \( 2 \times 3\sqrt{3}\)
= \(6\sqrt{3}\)