Respuesta :

Answer:

Radius=9

More Specific: 8.94427191

Step-by-step explanation:

a^2+b^2=c^2

a is the radius of circle A

b is 8

c is 12

a^2+8^2=12^2

Simplify

a^2+64=144

Move 64 to the other side

a^2=80

a=8.94427191

or 9