What is the distance between (-54) (-36)?

Answer 1

First of all, a meridian can be drawn at any longitude, there's no standard set

of them, and there are actually an infinite number of possible different ones.

So in order to get anywhere with this question, you'd have to specify which

two of them you're interested in.

But even if you named two meridians, there's no single answer to the question,

because the distance between any pair of meridians changes. They're farthest

apart where they cross the equator, and ALL meridians come together at a single

point at the north and south poles.

The distance in one degree of longitude is about 69 miles on the equator, and it

shrinks smoothly to zero at the poles.

The distance between any two meridians is

(69 miles) x (degrees of longitude between them) x (cosine of the latitude where you measure it).