Question

pls explain how to do this .....thanks ​

Answer 1

Answer:- 14cm

Step-by-step explanation:

Area of outer circle -Area of inner circle=Area enclosed between them.

so, πR²-πr²=770cm²

22/7x(21)²-22/7xr²=770cm²

22/7x441-770=22/7r²

(22x63)-770=22/7r²

1386-770=22/7r²

616/22/7=r²

616x7/22=r²

4315/22=r²

196=r²

r=√196

>>r=14cm

I hope it helps you

please mark this as brainliest