question_answer

The equation of a circle with origin as centre and passing through the vertices of an equilateral triangle whose median is of length 3a is

A)  \[{{x}^{2}}+{{y}^{2}}=9{{a}^{2}}\]

B)  \[{{x}^{2}}+{{y}^{2}}=16{{a}^{2}}\]

C)  \[{{x}^{2}}+{{y}^{2}}=4{{a}^{2}}\]

D)      \[{{x}^{2}}+{{y}^{2}}={{a}^{2}}\]