Porisma

A hint to get started

Extend a segment and use two vectors based at the angle vertex

Relative to O, A,B,C have position vectors 7i+6j−k7\mathbf i+6\mathbf j-\mathbf k, −11i−3j+26k-11\mathbf i-3\mathbf j+26\mathbf k, and 4i+j+7k4\mathbf i+\mathbf j+7\mathbf k. P lies on BA produced such that 3AB=PB.

(i) Find the position vector of P. marks

(ii) Find angle ABC. marks

(iii) Find the exact area of triangle ABC. marks

CJC · Review problems · Question 6

Put both angle vectors at B; draw the external division before using a section formula.

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