Final answer:
Radiocarbon dating showed King Richard III died in 1485 by analyzing the remaining carbon-14 in his tissue samples, which was about 93.79% of the expected amount in living tissue.
Step-by-step explanation:
Radiocarbon dating of tissue samples from the skeleton of King Richard III revealed that he died in the year 1485. This conclusion was drawn based on the measurement that the tissue contains about 93.79% of the carbon-14 expected in living tissue. The analysis of the carbon-14 remaining in biological materials like bone or tissue helps establish the time elapsed since the organism's death, utilizing the half-life of carbon-14, which is 5730 years. Knowing the half-life and the percentage of carbon-14 remaining allows archaeologists and historians to calculate the date of death of an artifact's source.