8.139 rounded to the nearest tenth would be 8.1 because the tenth place that we’re looking at is the number 1 and the number after it is 3. if the number that is after the tenth place is greater than 5 then the tenth place number goes up. and if the number after tenth place is lower than 5, then we stay the same. since 3 is lower than 5, the tenth place number stays the same making the answer 8.1. hope that helped lol..