
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
Carl is standing at point $C$ near the equator in Gabon at $0^\circ$ latitude and $10^\circ \text{ E}$ longitude. Dana is standing at point $D$ in the city of St. Petersburg, Russia, at $60^\circ \text{ N}$ latitude and $30^\circ \text{ E}$ longitude. Assume the Earth as a perfect sphere with the center $E$. What is the degree measure of $\angle CED$?

Present the answer in LaTex format: \boxed{Your answer}
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