Is this your area?
A salesperson normally covers what is called an area. In this case the area represents various counties and towns in which the salesperson will try to sell their goods.
When someone says "Is this your area?" they are saying "Is this part of your field of expertise?".
Area is a word we use to describe space when looking at a 2D (two dimensional) picture.
The area of 3D shapes (e.g. cubes, balls, tin cans etc.) is normally called surface area. It's the area taken up by whatever is around the shape.
If you go and buy a fitted kitchen, the shop asks you for the current measurements of your kitchen and any of the things in it - fridge, washing machine etc. You take the measurements along to a sales advisor who will plug the details into a computer system and show you your kitchen drawn onto a grid (criss-cross squares). Normally kitchen units are of standard sizes so the grid can be made to represent for example 2 centimetres per metre. Next the images of your glorious new fitted kitchen can be added to the grid of your current kitchen so that you can see in detail how much money you will be expected to part with.
Grids are used in a similar way in various design jobs to make placement and understanding of objects easier. A knowledge of area when using grids will make things much easier, particularly when dealing with shapes that are a bit more complex than the squares and rectangles of kitchen cabinets.
Finding the areas of shapes when you have a grid is really easy - all you do is count the squares. Imagine all the following grids have squares which are 1cm by 1cm - the area of each 1 by 1 square is 1cm2 (more maths shorthand which means one centimetre squared).
Here is an object which could be the shape of someone's kitchen (when looking down from above):
What is the area of the kitchen? Count the squares ticking off each one when you've counted it so as not to lose count which will give the answer 17. If you are told that each square represents a metre in the actual kitchen, then the area is 17m2. If each square represented 2 metres then the area would be 17 lots of 2m2 squares which is 34 m2 and so on.
Of great interest to builders is the distance around the shape. Imagine that this is the plan for a room in a house. The builder needs to know how many bricks to buy to make the room, in addition to the height of the room and the height and length of the bricks, the builder will also need to know the distance around all the walls - this is also called a perimeter. You may have heard of the perimeter of a playing field before (handy for grounds maintenance staff to know, so that they don't run of out whitewash just before the big match).
To work out the perimeter you need to count how many squares are covered by each line and add them together i.e. 3 + 5 + 4 + 2 + 1 = 15m.
Areas of triangles
There is a really easy way to work out the area of a triangle - Make it into a rectangle and divide the answer by 2!
Have a look at the triangle below:
You can see that there are 6 whole squares in the triangle and what seem to be 4 half squares, add the four half squares together then add to the number of whole squares already counted and you get the answer 8 (which is correct , but note that this gets much harder when you try to calculate the area of triangles with sides of different lengths!)
The quick way which works for all triangles is to make the triangle into a rectangle (the dotted line in the picture below shows where the line of the original triangle was).
The area of a rectangle (or square) can also be worked out by simply multiplying the lengths of each side together - you can still count squares if you really want to (though you'll really be stuffed if you don't have a grid). In the picture above, the area of the rectangle = 4 x 4 = 16cm2. Divide this by 2 which gives the area of the triangle = 8cm2.
With these simple methods of finding the area of a rectangle and the area of a triangle, you'll be able to calculate the areas of more complex shapes by breaking the areas down into rectangles and triangles, calculating the areas of each and adding them all together.
