Final answer:
Appeasement was the policy followed by the British and French to allow Hitler to take the lands he wanted, in hopes of avoiding war. However, this policy ultimately failed.
Step-by-step explanation:
The policy followed by the British and the French in allowing Hitler to take the lands he wanted in hopes of avoiding war is known as appeasement.
Appeasement was a strategy adopted by the French and British governments in the 1930s. They believed that by giving in to Hitler's demands for territory, they could prevent another world war from breaking out.
However, appeasement ultimately failed, as Hitler continued to expand his empire, leading to the outbreak of World War II.