Help me please im not good with rounding decimals

Use the frequency distribution, which shows the number of american voters (in millions) according to age, to find the probability that a voter chosen at random is in the 18 to 20 years old age range. ages frequency 18 to 20 5.9 21 to 24 7.7 25 to 34 20.4 35 to 44 25.1 45 to 64 54.4 65 and over 27.7 the probability that a voter chosen at random is in the 18 to 20 years old age range is nothing. (round to three decimal places as needed.)

Aball is dropped from a height of 10m above the ground. it bounce to 90% of its previous height on each bounce. what is the approximate height that the ball bounce to the fourth bounce?

Find the interior angle of a regular polygon which has 6 sides