How Do You Calculate the Resultant Displacement in a Football Pass Scenario?

[joedango]

In a game of American football, a quarterback takes the ball from the line of scrimmage, runs backward for 10.5 yards, and then runs sideways parallel to the line of scrimmage for 15.0 yards. At this point, he throws a forward pass 55.0 yards straight downfield perpendicular to the line of scrimmage. What is the magnitude of the football's resultant displacement?

From my drawing I get a right triangle with one side being 15 yd and the other side being 55 yds. In my attempt I do magnitude = , but 57.01 is not the right answer. What am I doing wrong?

 

[Spinnor]

You are forgetting the part where he runs back 10 yards.

 

[Spinnor]

See maybe:

http://hyperphysics.phy-astr.gsu.edu/hbase/vect.html

 

[joedango]

Oh I got it thanks!