Question 1Paper 1 style
Which one of the following is a great circle on the Earth's surface?
QCE General Maths Earth geometry and time zones
On the same meridian, the distance in kilometres is 111.2 times the angular distance in degrees. On the same parallel of latitude, it is 111.2 times the cosine of the latitude times the angular distance. Fifteen degrees of longitude is one hour of time.
| Paper 1 | Short response and multiple choice, 30% |
|---|---|
| Paper 2 | Short response, 20% |
| Each paper | 5 minutes perusal, 90 minutes working |
| Allowed | A scientific calculator and the formula book |
Angular distance first
- Same meridian, same hemisphere: subtract the latitudes. Opposite hemispheres: add them.
- Same parallel, same side of the prime meridian: subtract the longitudes. Opposite sides: add them, and take 360 degrees minus the sum if it is over 180.
- Convert minutes to a decimal first: 30 minutes is half a degree.
Time zones
- Each 15 degrees of longitude is one hour; each degree is four minutes.
- Places east of another are ahead in time. Crossing the International Date Line westward adds a day.
- Daylight saving moves a place's clock forward one hour: check which places use it on the date in the question.
Try 2 questions
Question 2Paper 1 style
Which one of the following statements is true?
Next step
Questions people ask
Why does the parallel formula use the cosine of the latitude?
A parallel of latitude is a smaller circle than the equator, and its radius shrinks by the factor cos(latitude), so each degree of longitude along it is shorter.
What is the difference between GMT and UTC?
Both are the reference time at the prime meridian; UTC is the precise international standard that time zones are given against.