Final answer:
King Suryavarman II was the most powerful figure in the formation of Angkor for constructing Angkor Wat. King Jayavarman VII also greatly contributed with his extensive city planning and public health initiatives. King Yasovarman I established the capital and is also remembered for his contributions.
Step-by-step explanation:
The most powerful figure in the formation of Angkor was King Suryavarman II, who was responsible for constructing the grand religious complex known as Angkor Wat around 1122 CE. This massive undertaking signifies the height of Khmer architectural achievement and took 30 years to complete. King Jayavarman II was also significant as the founder of the Khmer Empire and for declaring independence from Java. However, King Jayavarman VII is often celebrated as one of the greatest kings due to his extensive contributions, including the building of the walled city of Angkor Thom and improvements in infrastructure and public welfare by developing roads, traveller's houses, and hospitals throughout the empire. King Yasovarman I is notable for establishing a new capital, Yasodharapura, the nucleus of Angkor, and constructing the East Baray, a large reservoir.