The right angled triangle is missing, so i have attached it.
Answer:
Proved below
Explanation:
From the attached image, we can see that QP is parallel to BC.
Now, looking at triangles AQP and ABC, we can see that;
∠ AQP = ∠ ABC
Also;
∠ APQ = ∠ ACB
This means that triangles ABC and AQP are similar.
We are told that P is the mid-point of AC.
Thus; AP = PC
We can now say that;
AP:AC = 1:2 and AQ:AB = 1:2
Since AQ:AB = 1:2, it means Q is the midpoint of AB.
Now, ∠ AQP = ∠ BQP
However, according to SAS congruence test, AQP is congruent to BQP.
Thus; AP = BP = CP
Since AP:AC = 1:2 as we saw earlier, then;
BP:AC = 1:2
Thus:
BP/AC = ½
BP = ½AC