Latitude and longitude are how a sectional names a point when "near the airport" is not precise enough. The Part 107 test asks two versions. One is the definition. The other is a unit conversion from decimal degrees into degrees and minutes. A third, closely related item asks which printed numbers are magnetic instead of true. The three are easy to mix because they all live on the same chart.
The two directions
Latitude is angular distance north or south of the equator. Lines of latitude run east-west across the chart. Longitude is angular distance east or west of the Prime Meridian, the line through Greenwich. Lines of longitude, the meridians, run north-south and meet at the poles. The trap answer swaps them: it says latitude is measured east and west from Greenwich, or it says both are measured from the equator. Only latitude is measured from the equator. Only longitude is measured from Greenwich.
On a sectional the ticks along the edge mark degrees and minutes. The Chart Users' Guide describes the Maximum Elevation Figure quadrants as the areas bounded by ticked lines dividing each 30 minutes of latitude and each 30 minutes of longitude. You do not need the MEF to answer a pure lat/long item, but the ticks you use to locate a point are the same ticks that box the MEF. Figure 21, the Minot–Garrison excerpt, is the course figure that shows those ticks in the same view as MOA airspace. Locate the point first. Then decide what airspace the point sits in. The skills are separate.
Decimal degrees to minutes
A degree contains 60 minutes. To convert a decimal latitude, multiply the fraction by 60. A position given as 41.25°N, with no chart in front of you, is 41 degrees plus 0.25 times 60 minutes. That product is 15, so the latitude is 41°15'N. It is not 41°25'N. The digits after the decimal are not the minute count. It is also not 41°2.5'N from sliding the decimal point. The same arithmetic works for longitude.
If a question gives you the minutes already, do not convert them again. 41°15'N is already in degrees and minutes. 41.25°N is the decimal form of that same latitude. The same step on a different number: 32.50°N is 32°30'N, and 32.75°N is 32°45'N. Half a degree is 30 minutes. Three quarters of a degree is 45 minutes. The digits after the decimal are a fraction of a degree, not a minute count you can copy.
If a question asks for a distance in nautical miles, it is asking a different skill than this conversion. The lat/long items tied to this page ask which direction each coordinate measures, and how to turn a decimal degree into degrees and minutes.
True meridians, magnetic runways
Chart meridians point to true north. The numbers around a VOR compass rose are oriented to magnetic north. Runway numbers are the magnetic heading, rounded to the nearest 10 degrees. Runway 15 is about 150 degrees magnetic, not a latitude. Isogonic lines, where the chart prints them, show the variation between magnetic north and true north. The test item is the category, not a conversion: if the question asks what the compass rose and the runway numbers are referenced to, the answer is magnetic north, not true north and not grid north.
METAR wind is a different true-north product. Wind in a METAR is degrees true. Do not "correct" it to the runway number without being asked. That decoding lives on the METAR page.
Using the grid on a real question
When a figure question says "area 2" or describes a point, the ticks tell you which box. Read the latitude ticks on the side and the longitude ticks on the top or bottom. Then read the airspace symbol inside the box, using the symbol and airspace class pages. A correct lat/long conversion does not answer an airspace question, and a correct airspace read does not fix a swapped equator and Greenwich.
