Problem: The radius of the first circle is 1 inch, that of the second 1/2 inch, that of the third 1/4 inch and so on indefinitely. The sum of the areas of the circles is
Answer Choices:
A. 3Ο/4
B. 1.3Ο
C. 2Ο
D. 4Ο/3
E. none of these
Solution:
S=Ο+4Οβ+16Οβ+β―,S=Ο/[1β(1/4)]=4Ο/3.