How are radioactive dating and relative dating the same?

The main difference between relative dating and radiometric dating is that relative dating is the method used to determine the age of rock layers according to their relative depth whereas radiometric dating is the method used to determine the absolute age with the use of decaying products of the natural radioactive

How can radiometric dating and relative dating be used together to date the age of the Earth?

To establish the age of a rock or a fossil, researchers use some type of clock to determine the date it was formed. Geologists commonly use radiometric dating methods, based on the natural radioactive decay of certain elements such as potassium and carbon, as reliable clocks to date ancient events.