← Earth Geometry and Time Zones › Latitude and Longitude › Solutions
Solutions — Latitude and Longitude
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Fluency Coordinates of given points.
(a) North Pole: (90°N, any longitude) — the North Pole has latitude 90°N but longitude is undefined (all meridians meet there).
(b) On the equator at the prime meridian: (0°, 0°)
(c) (45°S, 90°W) — this is how coordinates are written (lat, long). -
Fluency Which is further from the equator: 30°N or 55°S?
30°N is 30° from the equator.
55°S is 55° from the equator.
55°S is further from the equator by 55 − 30 = 25 degrees. -
Fluency Longitude difference between 20°N, 30°E and 20°N, 80°E.
Both are east of the prime meridian, so: 80° − 30° = 50°
The cities are 50 degrees of longitude apart. -
Fluency Hemispheres for (42°S, 174°E).
42°S → Southern Hemisphere
174°E → Eastern Hemisphere
(This is near Wellington, New Zealand.) -
Understanding Brisbane (27.5°S, 153°E) and Sydney (34°S, 151°E).
Difference in latitude: 34° − 27.5° = 6.5°
Brisbane is at 27.5°S and Sydney is at 34°S. Brisbane is closer to the equator (smaller latitude value means closer to equator). -
Understanding Two ships at (0°, 30°W) and (0°, 60°E).
Angular separation: 30° + 60° = 90° (opposite sides of prime meridian, so add)
Distance along equator:
d = (2π × 6400 × 90) / 360 = (2π × 6400) / 4 = π × 3200 ≈ 10 053 km -
Understanding Plane flies from (10°S, 140°E) to (20°N, 140°E).
Angular change in latitude: 10° + 20° = 30° (crosses equator, so add)
Distance: d = (2π × 6400 × 30) / 360 = (2π × 6400) / 12 ≈ 3 351 km -
Understanding Cities on the same meridian / same parallel.
Same meridian (longitude): Examples — London (0°) and Accra, Ghana (0°); or Brisbane (≈153°E) and Tokyo (≈140°E, not exact but close).
Same parallel (latitude): Examples — Perth, WA (≈32°S) and Buenos Aires, Argentina (≈34°S, close); or Madrid, Spain (≈40°N) and New York (≈40°N).
(Many valid answers exist — the key concept is that same longitude means on the same north-south line; same latitude means on the same east-west ring.) -
Problem Solving Points A (40°N, 20°W) and B (40°S, 20°W).
(a) A and B are on opposite sides of the equator: angular difference = 40 + 40 = 80°
(b) Distance along meridian:
d = (2π × 6400 × 80) / 360 = (2π × 6400 × 2) / 9 ≈ (80 424 × 2) / 9 ≈ 8 936 km
(c) Fraction of full circumference = 80/360 = 2/9 ≈ 22.2% -
Problem Solving Ship along Tropic of Capricorn from 115°E to 154°E.
(a) Longitude change: 154° − 115° = 39°
(b) Radius of the circle at 23.5°S:
r = 6400 × cos(23.5°) = 6400 × 0.9171 ≈ 5869 km
Distance = (2π × 5869 × 39) / 360 ≈ (36 875 × 39) / 360 ≈ 3 995 km ≈ 3 995 km