Relative dating is used to determine a fossils approximate age by comparing it to similar rocks and fossils of known ages. Absolute dating is used to determine a precise age of a fossil by using radiometric dating to measure the decay of isotopes, either within the fossil or more often the rocks associated with it.Relative dating is used to determine a fossils approximate age by comparing it to similar rocks and fossils of known ages. Absolute dating

How does relative dating work with fossils?

Relative dating places fossils in a temporal sequence by noting their positions in layers of rocks, known as strata. As shown in the diagram, fossils found in lower strata were typically deposited first and are deemed to be older (this principle is known as superposition).

Why couldnt the fish fossil or dinosaur skull be dated with either C14 or U 238?

The fish fossil and dinosaur skull couldnt be dated with either C14 or U238 because carbon can only back date up to 50,000 years and U238 can only back date up to 4.5 billion years. Both the fish fossil and dinosaur skull were older.