How Do You Calculate the Angle Theta for a Pendulum Near Mt. Everest?

[evan b]

Homework Statement

Estimate the angle theta of the pendulum bob if it is 4.80km from the center of Mt. Everest.

The Attempt at a Solution

Tan(theta) = (GMeverest/r^2)/g

I have been trying to use this formula, but i don't think its the right one?

 

[Kurdt]

I think that formula should be ok for an estimate.