It is aware of geography the pupil quite often it is offered to determine continent extent from the South on the North or from the West on the East. In practice architects face a similar task, for example. The similar technique of calculations is applied also in space researches. For performance of such tasks it is necessary to know a ratio between degrees of a grid of coordinates and the number of kilometers, characteristic of each concrete object in the Universe.
It is required to you
- - card with a coordinate grid;
- - ruler;
- - calculator.
Instruction
1. Extent of the continent is a distance between its extreme points. The northernmost, southernmost, westernmost and easternmost tips are known, they can be found in geographical reference books and encyclopedias. For example, the most southern point of Africa — Cape Agulhas, and the most western continental point of Eurasia — Cape Roca. Pay attention that continent extent usually is determined by continental extreme points. But it can be offered to find in a task also distance between extreme island points.
2. It is possible to find extreme points and on the map, paper or electronic. The northernmost tip — the most convex top dot of the continent. Below, respectively, there will be the most southern. Determine their width. If near at hand there is no reference book, look on what parallels there are both necessary for you point. Find the difference between indicators of these parallels. It will also be the continent extent from the North on the South expressed in degrees. Do not forget that parts of the same continent can be located in northern and southern hemispheres. In this case values of width are summarized. That is if you, for example, need to define distance between points 45 ° and 75 ° northern latitude, then it will be equal 30 °. If one point is on 45 ° northern, and the second — on 75 ° southern latitude, then the distance between them will make 120 °.
3. Determine continent extent from the North on the South in kilometers. Having looked at the card, you will see that all meridians are equal therefore also the number of kilometers in one degree will be identical too. It makes about 111 km. Having increased this number by the number of degrees, you receive extent in kilometers.
4. Extent from the West on the East in degrees is defined in precisely the same way, as from the North on the South. Find extreme points. Determine their coordinates — in this case to you the longitude, that is the meridian passing through each of these points is important. Calculate the number of degrees.
5. To find extent from the West on the East in kilometers, it is necessary to know the cosine of the angle corresponding to an indicator of this parallel. It is multiplied by equator degree size. It makes about 111 km. For more exact calculations use a few other indicator — 111.3 km.