Prove that if a plane has the intercepts a, b, c and if it is at a distance of p units from the origin, then 1a2+1b2+1c2=1p2
The equation of a plane having intercepts a, b, c, with X, Y and Z-axes respectively, is given by
xa+yb+zc=1 ⇒(1a)x+(1b)y+(1c)z−1=0
Distance of this plane from the origin (0, 0, 0,) is given to be p.
∴ p=∣∣1a.0+1b.0+1c.0−1∣∣√(1a)2+(1b)2+(1c)2⇒1p=√1a2+1b2+1c2
On squaring both sides, we get 1p2=1a2+1b2+1c2