The flag of Algeria has a 2:3 aspect ratio. It is divided vertically into two equal halves. The left half is green (Pantone 356 C), and the right half is white. In the center, there is a red crescent (Pantone 186 C) encircling a red five-pointed star (Pantone 186 C). The star is placed within the crescent with one point directed towards the fly end of the flag.

The geometric properties are as follows:

1. The circle that forms the crescent has its center on the vertical line dividing the flag and its diameter is 2/3rds of the flag width.
2. The outer circumference of the crescent is a circle with a diameter equal to 12/15ths of the flag width.
3. The inner circumference of the crescent is a circle with a diameter equal to 10/15ths of the flag width.
4. The five-pointed star is inscribed in a circle with a diameter equal to 3/10ths of the flag width. The circle's center coincides with the center of the crescent's circles.

These measurements and colors are based on the official specifications provided by the Algerian government.