A steel bar containing three segment with varying cross sections (left segment AB with diameter of 45 mm, middle segment BC with diameter of 35 mm

A steel bar containing three segment with varying cross sections (left segment AB with diameter of 45 mm, middle segment BC with diameter of 35 mm and right segment CD with diameter of 25 mm) is subjected to forces as shown in Figure 5. Determine the total elongation of the bar. Assume the modulus of elasticity for steel material, Est = 210 GPa.