Answer: Option D
:
D
Answer- (d) None of these
Solution:- Calculate the altitude of the equilateral triangle. Then according to the conditions given,
Diameter of the circle circumscribing the equilateral triangle= Altitude of the equilateral triangle + Diameter of the smaller cirlce.
Solve the above equation for the required answer.
Alternate Soln: The triangle’s dimension is used to calculate the radii of the outermost and the second circle.


Radius of the bigger circle: R=$\frac{\left(1.5\right)}{cos30}$; =$\sqrt{3}$ units.
Radius of smaller circle:
r = 1.5 tan 30. = $\frac{\frac{3}{2}}{\sqrt{3}}$ r= $\frac{\sqrt{3}}{2}$.
Radius of smallest circle:
$\frac{\left(\right(radiusofbiggest)-(radiusof{2}^{nd}\left)\right)}{2}$;
=$\frac{\sqrt{3}}{4}$
Hence ans: d (none of these)