# Latitude and Longitude

> Find any place on Earth with degrees north or south of the equator and east or west of Greenwich.

From Selective School Maths on WhizzNotes, free study notes for NSW students: https://whizznotes.com/selective-school-maths/latitude-and-longitude/. Updated 3 November 2026.
Year 11 and Year 12 boxes go deeper than the Year 10 text around them.

### Story time: The message in a bottle
A ship's captain finds a bottle floating in the ocean. Inside is a note: "Stranded on an island at 34°S, 151°E. Please send help!"

The captain spreads out her map. She finds the line 34° south of the equator and follows it until it crosses the line 151° east of Greenwich. The two lines meet just off the coast of... Sydney! It turns out to be a prank by a Year 6 class on a beach excursion.

Two numbers, **latitude** and **longitude**, are enough to pin down any spot on Earth. They are coordinates for a round planet.

**In short:** Latitude and longitude give any place's position on Earth. Latitude measures how far north or south of the equator a place is, from 0° to 90°, and longitude measures how far east or west of Greenwich it is, from 0° to 180°.

## Before you start

- Coordinates on a grid use two numbers (see Coordinates and the Number Plane).
- Angles are measured in degrees. A full turn is 360°.
- North, south, east and west (see Compass Directions and Maps).

## Two sets of lines

*Diagram: A world grid: the equator runs across the middle and the prime meridian runs up and down through Greenwich; north is up, south down, east right and west left*
*Latitude is measured up or down from the equator. Longitude is measured across from the prime meridian.*

### Key idea: Latitude: north or south
Lines of **latitude** (also called **parallels**) run across the map, like the rungs of a ladder. They measure how far **north or south** of the **equator** a place is.

The equator is 0°. The North Pole is 90°N and the South Pole is 90°S.

### Key idea: Longitude: east or west
Lines of **longitude** (also called **meridians**) run from pole to pole. They measure how far **east or west** of the **prime meridian** a place is. The prime meridian is 0° and passes through Greenwich in London.

Longitude goes up to 180°E and 180°W, which is the same line on the other side of the world.

### Exam tip: Remember which is which
**Lat**itude lines lie **flat** (across). **Long**itude lines are **long**, running from the top of the world to the bottom.

## Writing a position

Write **latitude first**, then longitude, each with its letter.

Sydney is about 34°S, 151°E. That means 34° south of the equator and 151° east of Greenwich.

### Watch out: Do not forget the letter
Just "34° and 151°" is not enough. 34°N, 151°E is a spot in the sea near Japan! The N, S, E or W is part of the answer.

## Australia on the grid

All of Australia is **south** of the equator and **east** of Greenwich, so every Australian city has S and E.

| City | Latitude | Longitude |
|---|---|---|
| Darwin | 12°S | 131°E |
| Cairns | 17°S | 146°E |
| Alice Springs | 24°S | 134°E |
| Brisbane | 27°S | 153°E |
| Perth | 32°S | 116°E |
| Sydney | 34°S | 151°E |
| Adelaide | 35°S | 139°E |
| Melbourne | 38°S | 145°E |
| Hobart | 43°S | 147°E |

A **bigger** south latitude means further **south**: Hobart (43°S) is further south than Darwin (12°S). A **bigger** east longitude means further **east**: Brisbane (153°E) is east of Perth (116°E).

## Around the world

| City | Position |
|---|---|
| Helsinki | 61°N, 25°E |
| Moscow | 56°N, 38°E |
| Rome | 42°N, 12°E |
| New York | 41°N, 74°W |
| Tokyo | 36°N, 140°E |
| New Delhi | 29°N, 77°E |
| Mexico City | 19°N, 99°W |
| Rio de Janeiro | 23°S, 43°W |
| Cape Town | 34°S, 18°E |
| Wellington | 41°S, 175°E |

New York and Mexico City have W because they are in the Americas, west of Greenwich. Cities in the northern half of the world have N.

### Challenge: Selective level: longitude and time
The Earth spins 360° in 24 hours, so it turns 15° every hour. Places 15° further east see the sun rise about an hour earlier.

Perth (116°E) and Sydney (151°E) are 35° apart. $35 \div 15$ is a bit more than 2, so sunrise in Sydney is a bit more than 2 hours earlier than in Perth.

Cape Town (34°S, 18°E) and Sydney (34°S, 151°E) have the same latitude, so they are the same distance south of the equator.

**Mind map**

```text
Latitude and longitude
  Latitude
    North or south
    From the equator 0°
    Up to 90°
  Longitude
    East or west
    From Greenwich 0°
    Up to 180°
  Writing
    Latitude first
    Always add N, S, E or W
  Australia
    South and east
    Sydney 34°S 151°E
```

## Quick summary

- Latitude measures north or south of the equator (0° to 90°).
- Longitude measures east or west of the prime meridian at Greenwich (0° to 180°).
- Write latitude first, then longitude, each with N, S, E or W.
- Australia is south and east, so its cities have S and E.
- The Earth turns 15° of longitude every hour.

## Quiz

Try these questions from the chapter quiz.

1. What is the latitude of the equator?
   - A. 0°
   - B. 90°
   - C. 180°
   - D. 45°
   - Answer: A. 0°. The equator is the starting line for latitude.

2. Longitude is measured east or west of which line?
   - A. the equator
   - B. the prime meridian through Greenwich
   - C. the Tropic of Capricorn
   - D. the South Pole
   - Answer: B. the prime meridian through Greenwich. The prime meridian at Greenwich is 0° longitude.

3. Sydney is at about 34°S, 151°E. What does the S tell you?
   - A. Sydney is south of Greenwich
   - B. Sydney is south of the equator
   - C. Sydney is in the south of Australia
   - D. Sydney is on the southern line of longitude
   - Answer: B. Sydney is south of the equator. Latitude is measured north or south of the equator.

The whole chapter quiz is on the page, for signed-in students: https://whizznotes.com/selective-school-maths/latitude-and-longitude/#quiz