This is a continuation from H2 Maths Tuition: Foot of Perpendicular (from point to line) (Part I).

## Foot of Perpendicular (from point to plane)

From point (B) to Plane ( )

## Equation (I):

Where does F lie?

F lies on the plane .

## Equation (II):

Perpendicular

## Final Step

Substitute Equation (II) into Equation (I) and **solve for k**.

## Example

[VJC 2010 P1Q8i]

The planes and have equations and respectively. The point has position vector .

(i) Find the position vector of the foot of perpendicular from to .

## Solution

Let the foot of perpendicular be F.

### Equation (I)

### Equation (II)

Subst. (II) into (I)

Solve for k, .

## H2 Maths Tuition

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