Problem: A circle with area A1​ is contained in the interior of a larger circle with area A1​+A2​. If the radius of the larger circle is 3 , and if A1​,A2​,A1​+A2​ is an arithmetic progression, then the radius of the smaller circle is
Answer Choices:
A. 23​​
B. 1
C. 3​2​
D. 23​
E. 3​
Solution:
Since A1​,A2​,A1​+A2​ are in arithmetic progression,