Question

Two non-intersecting circles one lying insides another arc of diameter a and b. The minimum distance between their circumference is c. The distance between their centre is

• A. $a-b-c$
• B. $a+b-c$
• C. $\frac{1}{2}(a-b-c)$
• D. $\frac{1}{2}(a-b)-c$

Answer 1

Answer: (C)

$\frac{1}{2}(a-b-c)$

Let the two circles with centre A and B have diameter a and b respectively. The required distance=$BA$
$=AC-BC$
$=AC-(BD+DC)$
$\frac{a}{b}-(\frac{b}{2}+c)$
$\frac{a}{2}-\frac{b}{2}-c=\frac{1}{2}(a-b)-c$