Question

The radius of the fourth concentric circle from the centre is 16cm. If each inner circle is smaller than the other in radius by 2cm, what is the diameter of the first circle from the centre?​

Answer 1

Step-by-step explanation:

Let the radius of the inner circle be r cm. Then,

(π×21×21)−πr

2

=770

π(441−r

2

)=770

7

22

×(441−r

2

)=770

r

2

=196

r=14 cm

Answer 2

Step-by-step explanation:

Sand is a granular material composed of finely divided rock and mineral particles. Sand has various compositions but is defined by its grain size. Sand grains are smaller than