The ratio of the areas of the concentric circles $x^2+y^2-$ $6 x+12 y+15=0$ and $x^2+y^2-6 x+12 y-15=0$ is

The ratio of the areas of the concentric circles $x^2+y^2-$ $6 x+12 y+15=0$ and $x^2+y^2-6 x+12 y-15=0$ is
  1. $1: \sqrt{2}$
  2. $1: \sqrt{3}$
  3. $1: 2$
  4. $1: 4$

Solution

Given $C_1=x^2+y^2-6 x+12 y+15=0$ and $C_2=x^2+y^2-6 x+12 y-15=0$ $\Rightarrow r_1=\sqrt{30}$ and $r_2=\sqrt{60}$ Now ratio of their areas $=1: 2$

Asked in: AP EAMCET 2022 (08 Jul Shift 1)

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