How can I calculate the area of a triangle defined by 2 vectors, of which I have the components? It is not a right-angled triangle.

Since the triangle is not right-angled, you can't calculate its area directly by taking the lengths of the 2 vectors, multiplying them and dividing by 2. The 2 vectors aren't necessarily the base and the height of the triangle. It's also not ideal to try and figure out the height from the vector components and then using the (base*height)/2 formula. It's very long, which means there are also many more chances of making a mistake.
Instead, a pretty direct way of calculating it is by using vector operations: in particular, the cross product. While the dot product calculates a number (related to the how much two vectors are "aligned"), the cross product's result is a vector, perpendicular to the plane containing the 2 starting vectors. However, the length of this vector (which you can calculate with Pythagoras' theorem), represents the area of the parallelogram defined by the 2 vectors of which the cross product is being calculated. Knowing that, we can deduce that the triangle defined by the 2 vectors is simply half the parallelogram: therefore, you must divide the cross product length by 2.