Three Dimensional Geometry Question 146

Question: Two spheres of radii 3 and 4 cut orthogonally The radius of common circle is

Options:

A) 12

B) $ \frac{12}{5} $

C) $ \frac{\sqrt{12}}{5} $

D) $ \sqrt{12} $

Show Answer

Answer:

Correct Answer: B

Solution:

[b] For the orthogonal section $ C_1P $ and $ C_2P $ are pendicular where $ C_1 $ and $ C_2 $ are centers of sphere of radii 4 and 3 respectively Now $ C_1P=4 $ and $ C_2P=3 $ , so $ \tan \theta =\frac{3}{4} $
$ \therefore $ Radius of circle of intersection $ OP=C_1P\sin \theta =4\times \frac{3}{5}=\frac{12}{5} $