The approximate value of √19 can be determined by finding the square root of 19, which falls between the integers 4 and 5.
On a number line, we can plot the integers 4 and 5 and determine the approximate value of √19 by estimating where it falls between these two points. Since 19 is closer to 16 than 25, we can estimate that √19 is closer to the square root of 16, which is 4.
Thus, the approximate value of √19 on the number line is 4.