The flag of Senegal has three equal vertical stripes, from left to right: green, yellow, and red. The official color codes are:

• Green: Pantone 355 C / RGB: 0, 152, 70 / Hex: #009846
• Yellow: Pantone 116 C / RGB: 255, 194, 0 / Hex: #FFC200
• Red: Pantone 186 C / RGB: 206, 17, 38 / Hex: #CE1126

The aspect ratio of the flag is 2:3. Its geometric properties and measurements are:

• The flag has a rectangular shape.
• The width of the flag is twice its length.
• The length of the flag is 150% of the height of the central stripe (the yellow one).
• The width of each stripe is 1/3 of the total width of the flag.

In summary, the flag of Senegal has three vertical stripes of equal size, in green, yellow, and red, with an aspect ratio of 2:3, and specific color codes and geometric properties.