The cartesian equation of the plane passing through (x1, y1, z1), the direction ratios of whose normal are a, b, c, is
The required plane is parallel to XY-plane.
∴ it is perpendicular to Z-axis i.e. Z-axis is normal to the plane. Z-axis has direction ratios 0, 0, 1.
The plane passes through (7, 8, 6).
∴ the cartesian equation of the required plane is 0(x – 7) + 0(y – 8) + 1 (z – 6) = 0
i.e. z = 6.
