Step of construction:
1. Draw a triangle which has AB = 5 cm, BC = 6cm , and CA = 7 cm
2. Draw an acute angle CBX below BC at point B .
3. Mark the ray BX as B1, B2 B3,B4 ....B7 such that BB1= B1B2................B6=B7
4.join B5 to C
5. Draw B7 C' || to B5C , where C' is extended line BC.
6. Draw A'C'|| AC where A' is a point on extended line BA.
7. A'BC' is required triangle