Final answer:
Dinosaurs went extinct around 65 million years ago during the Mesozoic Era, not 2,345 years ago. The T. rex evolved about 70.6 million years ago and was one of the last dinosaurs to exist. The time span of 2,345 years can be broken down into millennia, centuries, and decades but is far closer to our time than the age of dinosaurs.
Step-by-step explanation:
The student has misunderstood a key point about history: dinosaurs did not exist 2,345 years ago. Instead, the non-avian dinosaurs were already extinct by that time. Dinosaurs lived during the Mesozoic Era, which is also known as the Age of Dinosaurs. This era lasted from about 245 to 65 million years ago, ending with a mass extinction event commonly referred to as the "great dying." This calamitous period saw the demise of over half of Earth's species, including the non-avian dinosaurs.
As for the mathematical aspect of the question, to clarify, 2,345 years would equate to 2.345 millennia, 23.45 centuries, 234.5 decades, and, of course, the 2,345 years as stated. These conversions are necessary to understand the vast differences between the time periods discussed and the actual timing of the dinosaur extinction, which occurred 65 million years ago.
A fun fact related to these ancient creatures is that the Tyrannosaurus rex, one of the last and most iconic dinosaurs, evolved roughly 70.6 million years ago. Interestingly, humans are closer in time to the T. rex than it was to its earliest dinosaur ancestors.