Explanation:
believe it or not, the area of any triangle is
baseline × height / 2
we have here 2 triangles, both with the same baseline (8 cm), but with 2 different heights : 6.5 cm and 4.6 cm.
so, their areas are
8 × 6.5 / 2 = 4 × 6.5 = 26 cm²
8 × 4.6 / 2 = 4 × 4.6 = 18.4 cm²
so, in total, the shaded region is
26 + 18.4 = 44.4 cm²