Solved Examples & Practice

Crossword Solution (Page 25)

Based on the clues provided in the textbook:

Across

1. SCALE (Lets you squeeze a huge area into your map)
2. GLOBE (A convenient sphere)
3. EQUATOR (The longest parallel of latitude)
4. GREENWICH (The place the Prime Meridian is attached to)
5. MAP (So convenient to find your way)
6. LATITUDE (A measure of the distance from the Equator)

Down

2. LONGITUDE (A measure of distance from the Prime Meridian)
3. COORDINATES (These two together allow us to locate a place)
4. GRID (What latitudes and longitudes together create)
5. IST (The time we all follow in India)
6. POLE (On top of the world)
7. IDL (Abbreviation for the line where day/date change)

Logic Practice: Time Calculation

Question: If it is 10:00 AM at the Prime Meridian ($0^\circ$), what is the local time at $30^\circ \text{W}$?

Step-by-Step Solution:

1. Identify Longitude Difference: $30^\circ - 0^\circ = 30^\circ$.
2. Convert to Time: $15^\circ = 1$ hour, so $30^\circ = 2$ hours.
3. Determine Direction: $30^\circ \text{W}$ is to the West of the Prime Meridian.
4. Calculate: In the West, time is “behind.” $10:00 \text{ AM} - 2 \text{ hours} = 8:00 \text{ AM}$.

Answer: The local time is 8:00 AM.

Social Science Themes (From Introduction)