As you know from the school course of geometry to calculate the area of a rectangle, you multiply the length by the width. Accordingly, in order to find out the area of a room, multiply the length of its sides.
First begin by measuring the sides of the room. Do it better by using construction tape, which has a sufficient length and keeps a smooth shape. The length and width of the room measure along the walls. This frees up space near the wall and put the tape measure along the floor. Important to make sure that the measuring tapes are not twisted and not stretched excessively. The obtained data it is better to write down on a piece of paper so you don't have to measure again.
By measuring both sides of the room – length and width, and do the necessary calculations. For example, if the longest side is 5 m and 3 m, the area of the entire room will be 5x3 = 15 sq. m. it Should be note that if the lengths are always measured in meters, then the area of the surface of the floor or ceiling only in square meters.
In the absence of in house construction and roulette you can use to measure ordinary tailor's meter. But it is important to remember that in this case the accuracy of the results obtained will be much higher, because the tape bends easily and folds. Moreover, it is much shorter, so the length will have to measure, consistently moving a centimeter at uniform intervals.