Question

In the below figure, BC= ___.

• A. 4 cm
• B. 3 cm
• C. 6 cm
• D. 8 cm

Answer 1

The correct option is D 8 cm

Given that $OA\perp BC.$
Using Pythagoras' theorem in $△OAB,$ we have
$O{B}^2=O{A}^2+A{B}^2.$
$⟹5^2=3^2+A{B}^2$
$⟹AB=4cm$
We know that the perpendicular drawn from the centre of a circle to the chord bisects the chord.
$⟹AB=AC$
$⟹BC=2\times AB=2\times 4=8cm$