How to find the angle between r and the x axis?

[deaninator]

Homework Statement

How do I find the angle between r and the X axis?

Homework Equations

The Attempt at a Solution

My attempt is here:

https://www.physicsforums.com/attachment.php?attachmentid=29307&d=1287751693

However the computer says 69.3 degrees is incorrect.

 

[quantumdude]

You miscalculated r.

 

[fzero]

Recheck how you computed the expression for r. The expression with the square root looks ok, but I find that it evaluates to 4.6, not 8.5.

 

[deaninator]

Recheck how you computed the expression for r. The expression with the square root looks ok, but I find that it evaluates to 4.6, not 8.5.

Ok so i got 86.64 is that correct?

 

[fzero]

Looks right.