Question

Two concentric circles have radii of 10 cm and 5 cm respectively then what is the area of space between them?​

Answer 1

Step-by-step explanation:

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.