Problem 10-31(a) Vector electric field - B

The figure shows the positions of two a particles (charge on each is $+2e$) and an electron. What are the magnitude and direction of
(a) the resultant force on the electron?
(Hint: choose the $+x$ axis along the line from the electron to the right-hand a particle.)

[Ans.(a) $1.31 \times 10^{-8} N$ at $13.3^\circ$ to left of line from electron to right-hand a]

No. You do not know the angle between the $x$-axis and any side of the triangle.

Try again.