Open Question: How to find the direction of resultant vector?

Let the 20N vector be along x direction, so the 10N vector is along -x as they are 180deg apart.
10N vector on a +x scale would have magnitude of -10N in the +x dirn

So resultant would be the sum of them ie 20 + (-10) = 10 N in the direction of the 20N vector

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