waecmaths question:
A chord is 2cm from the centre of a circle. If the radius of the circle is 5cm, find the length of the chord.
Option A:
$2\sqrt{21}cm$
Option B:
$\sqrt{42}cm$
Option C:
$2\sqrt{19}cm$
Option D:
$\sqrt{21}cm$
waecmaths solution:
$\begin{align} & \left| AC \right|=\sqrt{{{5}^{2}}-{{2}^{2}}}=\sqrt{25-4}=\sqrt{21} \\ & AB=2\times \left| AC \right|=2\sqrt{21} \\\end{align}$
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