Question

what is the approximate latitude and longitude of the south American location marked by the black dot on this diagram

Answer 1

Answer: Latitude:$15\° S$ Longitude:$45\°W$

Explanation:

The diagram was not attached. However, I attached the image below with the marked dot.

Well, let's begin by explaining what Latitutde and Longitude are:

Latitude is defined as the angular distance between the equatorial line (the red line in the image) and a specific point on the Earth. Dividing the planet in the northern hemisphere and the southern hemisphere, depending on the location of the geographical point with respect to the equator.  

These are imaginary horizontal lines that never touch (that is why they are parallel) that travel across the Earth globe from East to West, forming circles that become smaller and smaller as they get closer to the poles. Where the equator line is known as parallel $0\°$, and the degrees of latitude reach up to $90\°$North or $90\°$South.

On the other hand, Longitude represents the specific east–west position of a point on the Earth's surface, being longitude $0\°$ the prime meridian or Greenwich meridian (magenta line).

So, in this case we have the globe divided in parallels in sections of $30\°$ each and something similar happens to the meridians.

As we can see, the black dot is in the middle of two parallels:

The Equator with latitude $0\°$ and latitude $30\° S$.

This means the latitude of this point is  $15\° S$.

Now, this same dot is in the middle of two meridians:

Longitude $30\° W$ and longitude $60\°W$

This means the longitude of this point is  $45\° W$.

Therefore, the coordinates of this points are:

Latitude:$15\° S$ Longitude:$45\°W$