Triangle TRS is congruent to QRP by SSS congruence.
To prove that
, we can use the Angle-Bisector Theorem. This theorem states that if a ray bisects an angle of a triangle, then it divides the opposite side into two segments that are proportional to the lengths of the other two sides.
In this case, we are given that
bisects
and
bisects
. This means that we have two pairs of proportional segments:
(because
bisects
)
(because
bisects
)
We can now use these two proportions to prove that
.
Proof:
1.
(given)
2.
(given)
3. Multiplying both sides of equations 1 and 2, we get:

4. Simplifying, we get:

5. By the Angle-Bisector Theorem, we know that

6. Substituting this into equation 4, we get:

7. Cross-multiplying, we get:

8. Dividing both sides by

9. Since PR = RP, we can conclude that
by the Side-Side-Side (SSS) Congruence Theorem.
Conclusion:
We have proven that
using the Angle-Bisector Theorem and the SSS Congruence Theorem.