Final answer:
The hepatic lobule is a triangular structure with a portal triad at its center and three angles formed by the central vein. It consists of hepatocytes and is responsible for processing nutrients, toxins, and waste materials carried by the blood.
Step-by-step explanation:
The triangular structure mentioned in the question is the hepatic lobule.
It is composed of liver cells called hepatocytes, which are arranged in rows around a central vein. The three angles formed by the central vein are known as the portal triad.
The portal triad consists of three structures: a hepatic artery branch, a hepatic portal vein branch, and a bile duct. These structures are responsible for supplying oxygen, nutrients, and bile to the liver.