What are some other examples of joints in your body that work like a hinge?

Knees and elbows are two of the most common ones.

It's known as the hinge joint. A primary example is your elbow, it can fold towards you, but if you try to bend it, it'll result in a break. Your knee is also a good example, especially since it's the largest hinge and pivot joint. Your fingers also have hinge joints as well.

Radon-222 or rn-222 has a half-life of 3.82 days. to determine the fraction of an original sample of rn-222 that remains unchanged after 7.646 days, we calculate the amount of rn-222 remaining after 7.646 days and divide it with the original amount. using 1 gram as a basis and using half-life calculation methods, we can determine that  0.249 or 0.25  grams of rn-222 will remain, and thus the fraction remaining is 0.25 or 1/4.