Two points P and Q are 3 cm apart. These two points lie on the circumference of a circle having radius 1.7 cm. What is the distance (in cm) of the line segment PQ from the centre of the circle?

Correct option is A

​​​PQ = 3 cm

Radius OP = 1.7 cm

The distance of a chord from the centre cuts the chord in half and perpendicular to it.

​$$OM \perp PQ \\PM = \frac{3}{2} = 1.5 \, \text{cm} \\\text{Now, By Pythagoras theorem} \\H^2 = P^2 + B^2 \\(1.7)^2 = OM^2 + (1.5)^2 \\OM^2 = 1.7^2 - 1.5^2 \\OM = \sqrt{(1.7 + 1.5)(1.7 - 1.5)} \\OM = \sqrt{3.2 \times 0.2} = \sqrt{0.64} \\OM = 0.8 \, \text{cm}$$​​