The concepts used to solve this problem are those related to the Pythagorean theorem for which we will calculate the distance and the pitch.
According to the attached diagram we have that the expression of the resulting displacement is
[tex]R = \sqrt{(3b)^2+(4b)^2}[/tex]
Therefore the resultant displacement of the girl is
[tex]R = \sqrt{(9b^2+16b^2)}[/tex]
[tex]R = \sqrt{25b^2}[/tex]
[tex]R = 5b[/tex]
Therefore the girl has displaced around of 5 blocks
