Answer:
Explanation:Following are the techniques or methods or approaches we can say that were used by the scientists to determine the geologic age:
1. Relative age dating
2. Absolute age dating.
3. Radiation measurement.
4. Stratigraphic superposition.
5. The fossil record.
The scientists used the method of relative dating to divide Earth's past in different chunks of time when alike organisms were on Earth. After that, to discover the actual number of years ago that events occurred, the scientists used the method of absolute dating.