Question

A chord of length 8 cm is drawn in a circle of radius 5 cm. Calculate its distance from the centre of the circle.

• A. 5 cm
• B. 1 cm
• C. 3 cm
• D. 2.5 cm

Answer 1

The correct option is C

3 cm

Let chord AB = 8cm

$\Rightarrow AC=CB=4cm$ [ the perpendicular from the centre of the circle bisects the chord]

$△OAC$ is a right angled triangle.

$\therefore O{C}^2=O{A}^2-A{C}^2$

$=5^2-4^2$

= 25 - 16 = 9

$\therefore OC=\sqrt{9}=3cm$