Theorem 6.7- if a ray bisects and angle of a triangle, then it divides the opposite side into segments whose lenghts are proportional to the lenghts of the other two sides.
example- shwon above. Triangle BAC is intersected by ray D.
test question 1) <QPR congruent to <RPS. find length of RS
STEP 1) RQ/RS = PQ/PS
STEP 2) 15-x/x = 7/13
STEP 3) 7x=195 - 13x
answer 1) x=9.75
STEP 1) RQ/RS = PQ/PS
STEP 2) 15-x/x = 7/13
STEP 3) 7x=195 - 13x
answer 1) x=9.75