Open Question: Calculate the distance or size (in meters) of each of the following objects:?

Please tell me the formulas so that I can learn how to do the following calculations:

Calculate the distance or size (in meters) of each of the following objects:

What is the height of a person standing 100 m away, whose visual angle is 1 deg?

What is the viewing distance if a coin that is 2 cm in diameter and forms a visual angle
of 2 deg?

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