How did Portugal find an ocean route to Asia

Vasco De Gama discovered the route.

Explanation:

The first European to find a successful trading route to India was Vasco De Gama. His discovery of the route helped the Portuguese establish a long lasting colonial empire in Asia and Africa.

He started his journey from Lisbon and sailed past the Canary Islands to  the Cape Verde islands then  sailed out into the South Atlantic and swung down to the Cape of Good Hope then  anchored at Mossel Bay, South Africa, then sailed to Mozambique at the Rio do Cobre (Copper River) and continued on until they reached the Rio dos Bons Sinais (River of Good Omens). Here they erected a statue in the name of Portugal. They then went to  the Island of Mozambique. After trading with the local Muslim merchants, da Gama sailed on once more stopping briefly in Malindi (in present day Kenya). He hired a pilot to help him navigate through the Indian Ocean. They sailed for 23 days, and on May 20, 1498 they reached India.

b. ensure mutual protection from communism.

.