Find the area of the circle 26 in. rounded to the nearest tenth

Me. i can't figure out this question. give an explanation too. .

Choose the more precise measurement. 26.4 cm or 8.39 cm

Monitors manufactured by tsi electronics have life spans that have a normal distribution with a standard deviation of 1800 hours and a mean life span of 20,000 hours. if a monitor is selected at random, find the probability that the life span of the monitor will be more than 17,659 hours. round your answer to four decimal places.