Distance of a point to a Plane
Calculate distance of a point (3,7,-4) to the Plane 6x-3y+2z = 10
Let the equation of the plane :
w1.i + w2.j + w3.k + w0 = 0
Then, W = w1.i + w2.j + w3.k be the perpendicular vector to the plane
vector(b) = vector(X)-vector(P)
Let X = a.i + b.j + c.k
and P = p1.i + p2.j+p3.kthen, vector(b) = (a-p1).i + (b-p2).j + (c-p3).k
Angle(PXO) = Angle(XPW) = Θ
And, CosΘ = d/b (since, base/hypotenuse= cosΘ)
d = b*CosΘVector(W)*Vector(b) = W*b*CosΘ (Vector Dot Product)
w1(a-p1) + w2(b-p2) + w3(c-p3) = W*d
W*d = w1*a + w2*b + w3*c -(w1*p1 + w2*p2 + w3*p3)
W*d = w1*a + w2*b + w3*c -(-w0)
d = (w1*a + w2*b + w3*c + w0)/W
d = (W *(dot_Product)X + w0) / Sqrt(w1² + w2² + w3²)
Lets solve this ‘Calculate distance of a point (3,7,-4) to the Plane 6x-3y+2z = 10’
Distance, d =( 6*3+3*(-7)+2*(-4)+(–10) ) / Sqrt(6²+3² + 2²)
d = -21/7 = -3