Calculating the distance from a certain place to the equator

So, let's say we have a certain place on earth and we want to roughly calculate the shortest distance from that place to the equator. Is my method correct:

Since the earth is roughly a sphere, we just take the circumference of the earth. We then divide it by 180 (since the earth is divided in 180 degrees, ranging from 90N to 90S). Then we just take the place on the equator with the corresponding longitude, and we just take the latitude of the place and we know how much distance 1 latitude is since we calculate that earlier, and the rest is child's play. Is this correct?

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Yes indeed, we just take half of the circumference. –  Isthiscorrect Dec 30 '12 at 16:05