1. **Problem statement:** Calculate the area of the shaded portion of the triangle with two equal sides of length 8 cm and an included angle of 54°. 2. **Formula used:** The area $A$ of a triangle with two sides $a$ and $b$ and included angle $\theta$ is given by: $$A = \frac{1}{2}ab\sin(\theta)$$ 3. **Given values:** - $a = 8$ cm - $b = 8$ cm - $\theta = 54^\circ$ 4. **Calculate the area:** $$A = \frac{1}{2} \times 8 \times 8 \times \sin(54^\circ)$$ 5. **Evaluate $\sin(54^\circ)$:** Using a calculator or sine table, $\sin(54^\circ) \approx 0.8090$ 6. **Substitute and simplify:** $$A = \frac{1}{2} \times 64 \times 0.8090 = 32 \times 0.8090 = 25.888$$ 7. **Final answer:** The area of the shaded portion is approximately **25.89 cm²**.