How many years did it take for dred scott v. sandford to reach the supreme court?

It took around 10 years. The first attempt of Scott in Missouri court after trying to buy his freedom with the help of abolitionist groups and being unsuccessful, was in 1846. After many failed attempts, the case finally reached US Supreme Court in 1856 and decided in 1857, not in favor of Scott and his pursue of obtaining the rightful american citizenship. The judge decided that no individual of African descent, whether slave or free, had the right to appeal to Supreme Court.

The answer is 10 yrs

radioactive dating, also known as  radioisotope dating  is a process that in  estimating the approximate  age  of  rocks. these data can be analyzed from  the studies dealing with the  decay of the radioactive elements that are present in these rocks. in nature, there are a few types of materials or atoms which are quite unstable and they spontaneously decay or breakdown to form other kinds of atoms.