Since P is equidistant from lines AB and AC through point A, it lies along the angle bisector direction. The unit vectors are u^AB=113i+j−k and u^AC=11i−j+3k.
The bisector direction is proportional to 2i+k, so AP=λ(2i+k).
From ∣AP∣=25: ∣λ∣5=25, giving λ=21.
Thus AP=i+21k.
Area of triangle ABP = 21∣AB×AP∣.
Computing: AB×AP=21i−25j−k.
∣AB×AP∣=41+425+1=430=230.
Area = 430.