During which decade did the us pursue a policy for isolation

the 1930s
Explanation: The USA watched carefully the rise of fascism in Europe and Japanese expansion in Asia, but did not intervene, There was a strong isolationist lobby and many had sympathy with both Hitler and Mussolini who they saw as leaders who were putting to rights, the problems of their countries, and were also important bulwarks against communism.
It took the Japanese attack on Pearl Harbour to bring the USA into the war and even then there was no guarantee they would have become directly involved in the conflict in Europe. It was Hitler who declare war on the USA in support of his Japanese Axis allies.

Remember soh-cah-toasoh: cah: toa: now, looking at the picture we can see that we have an angle, the hypotenuse and want to find the value of the adjacent side to the angle. so we use cah to find the adjacent angle. plug in what we have: we need to solve for x now so we get it by itself on one side: plug this into your calculator and you'll find that:

Aor b but i'm going with b