The plane of a dip circle is set in the geographic meridian and the apparent dip is $\delta_1$. It is then set in a vertical plane perpendicular to the geographic meridian. The apparent dip angle is $\delta_2$. The declination $\theta$ at the place is

• A

  $\theta=\operatorname{Tan}^{-1}\left(\tan \delta_1 \cdot \tan \delta_2\right)$
• B

  $\theta=\operatorname{Tan}^{-1}\left(\tan \delta_1+\tan \delta_2\right)$
• Correct answer
  C

  $\theta=\operatorname{Tan}^{-1}\left(\frac{\tan \delta_1}{\tan \delta_2}\right)$
• D

  $\theta=\operatorname{Tan}^{-1}\left(\tan \delta_1-\tan \delta_2\right)$

Hence, the correct answer is option: 'C'.