Problem 439:
Given a point $M_{b}$, a point $T_{b}$ and a point $I$, construct the triangle ABC.

Construction: 
1. Using the point $M_{b}$ and the point $T_{b}$, construct a line $b$ (rule W02);
2. Using the point $T_{b}$ and the point $I$, construct a line $s_{b}$ (rule W02);
3. Using the point $M_{b}$ and the line $b$, construct a line $m_{b}$ (rule W10b);
4. Using the line $m_{b}$ and the line $s_{b}$, construct a point $N_{b}$ (rule W03);
5. Using the point $I$ and the point $N_{b}$, construct a circle $k(N_{b},A)$ (rule W06);
6. Using the circle $k(N_{b},A)$ and the line $b$, construct a point $A$ and a point $C$ (rule W04);
7. Using the point $I$ and the line $b$, construct a circle $k(I,P_{a})$ (rule W11);
8. Using the circle $k(I,P_{a})$, the point $A$, the point $I$ and the line $b$, construct a line $c$ (rule W13);
9. Using the line $c$ and the line $s_{b}$, construct a point $B$ (rule W03);
10. Using the point $C$ and the point $A$, construct a point $\_M_{b}$ (rule W01);
11. Using the point $A$ and the point $B$ construct the line $\_c$ (rule W02);
12. Using the point $B$ and the point $C$ construct the line $\_a$ (rule W02);
13. Using the point $C$, the point $B$ and the point $A$ and the line $\_a$ and the line $\_c$ construct the angle bisector $\_s_{b}$ (rule W17);
14. Using the point $A$ and the point $C$ construct the line $\_b$ (rule W02);
15. Using the line $\_s_{b}$ and the line $\_b$ construct the point $\_T_{b}$ (rule W03);
16. Using the point $B$, the point $A$ and the point $C$ and the line $\_c$ and the line $\_b$ construct the angle bisector $\_s_{a}$ (rule W17);
17. Using the line $\_s_{a}$ and the line $\_s_{b}$ construct the point $\_I$ (rule W03);

Statement:
Prove that the point $M_{b}$ is identical to the point $\_M_{b}$.

