To calculate the area by mathematical drawing, we only need to know the length, width and height of the required area, and then we can calculate the area of the required figure according to the area calculation formula.

The basic methods commonly used to calculate the area are:

1, add.

This method is to decompose an irregular figure into several basic regular figures, calculate their areas respectively, and then add them to find the area of the whole figure.

2. subtraction.

This method regards the area of irregular figure as the difference of several basic regular figures.

3. Seek the law directly.

This method is based on the known conditions, and directly obtains the area of irregular graphics as a whole.

4. Reorganization method.

This method is to disassemble the irregular figure, reassemble it into a new figure according to the specific situation and the needs of calculation, and try to find out the area of this new figure.

5. Auxiliary line method.

This method is to add one or more auxiliary lines to the graph according to the specific situation, so that the irregular graph can be transformed into several basic regular graphs, and then add and subtract to solve it.