Question

1. The diameter of a circle is 10 cm. It has a chord of length 8 cm. Then the distance .. cm of the chord from the centre is 1) 9 277 3) 8 4) 3 [​

Answer 1

OB⊥AC

In ΔOAB,

OB

2

+AB

2

=5

2

(Pythagoras theorem)

⇒3

2

+AB

2

=5

2

⇒AB

2

=5

2

−3

2

=4

2

∴ AB=4cm

Similarly BC=AB=4cm

∴ length of the chord touching the smaller circle is (4+4)=8cm.