Answer
The y-component of the vector is 6 m
Work Step by Step
Since the vector is in the first quadrant, the y-component of the vector is positive. Therefore;
$x^2+y^2 = (10~m)^2$
$y^2 = (10~m)^2 - x^2$
$y = \sqrt{(10~m)^2 - x^2}$
$y = \sqrt{(10~m)^2 - (8~m)^2}$
$y = 6~m$
The y-component of the vector is 6 m.