The flag of Guyana, also known as "The Golden Arrowhead," has an aspect ratio of 3:5. It consists of a green field with a red isosceles triangle on the hoist side, bordered by a narrow white stripe and a larger black stripe. A yellow isosceles triangle extends from the center towards the fly side, bordered by a narrower golden (orange) stripe.

Color codes:

1. Green: Pantone 349 C, Hex #006A44
2. Red: Pantone 186 C, Hex #CE1126
3. Yellow: Pantone 123 C, Hex #FCD116
4. Black: Pantone Black C, Hex #000000
5. White: Pantone White C, Hex #FFFFFF
6. Golden (Orange): Pantone 137 C, Hex #FF9627

Geometric properties and measurements:

1. The green field covers the entire flag.
2. The base of the red triangle is equal to the width of the flag, and its height is 3/5 of the flag's length.
3. The white and black border stripes are parallel to the red triangle sides, each having a width equal to 1/30 of the flag's length.
4. The base of the yellow triangle is equal to 21/50 of the flag's length, and its height is 3/5 of the flag's length.
5. The golden (orange) border stripe is parallel to the yellow triangle sides, with a width equal to 1/30 of the flag's length.