Why did the united states announce the open door policy?

Earn more profit.

Explanation:

The Open Door Policy allowed America to have access to the consumers of other countries such as China and Europe. It also protected trade between China and established a good relationship between the two countries.

for the united states of america, 1945 to 1964 was a time of high economic growth and general prosperity. it was also a time of confrontation as the capitalist united states and its allies politically opposed the soviet union and other communist countries; the cold war had begun.

explanation: