Vector problem with electricity

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The discussion revolves around a vector problem involving four identical point charges arranged in a rectangle, where the user is calculating the net electric force on one charge. The calculations for individual forces (F1, F2, F3) are presented, but the user suspects an error in determining the overall force magnitude, which they calculate as 1530N. The angle calculated is correct, leading to confusion about the force magnitude discrepancy. A suggestion is made to check unit conversions, particularly from centimeters to meters, which may be the source of the error. The user seeks further assistance to resolve their vector issues.
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vector problem with electricity :(

Ok, so i am having problems with my vectors in two homework problems (or maybe i went wrong some where else)...

#1) Four identical point charges (q = +10.0 µC) are located on the corners of a rectangle. The dimensions of the rectangle are L = 70.0 cm and W = 25.0 cm. Calculate the magnitude and direction of the net electric force exerted on the charge at the lower left corner by the other three charges.

ok, so i drew a lovely picture of the rectangle with all three force vectors as repulsion. my work goes something like this:
F1= 8.99e9 * 10e-6 ^2 / .025^2 = 1438N
F2= 8.99e9 * 10e-6 ^2 / (.025^2+ .07^2) = 163N
F3= 8.99e9 * 10e-6 ^2 / .07^2 = 183.5N

Then made a vector table:

F1 x components = 0 and y components = 1438N
F2 x components = 163cos19.65= 153N y components...=54.7N
F3 x components = 183.5 N and y = 0

I then added up the x to get Fx=337N and Fy=1493N

then F= (337^2 + 1493^2) ^1/2 = 1530N (but that's wrong)

but then i got the angle by taking hte inverse tan of 1493/337 = 257degrees and that is correct, so i don't really know why my force magnitude is worng... and i have another problem on my homework that is similar and i keep getting it wrong too, so i think i am doing something wrong with my vectors... any ideas or help would be greatly appreciated. THANKS!
 
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Check your unit conversions (specifically going from centimeters to meters).
 
Thread 'Variable mass system : water sprayed into a moving container'
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