an equilateral triangle of side 8.9 cm .

Did you know that the area of an equilateral triangle can be calculated using the formula \( A = \frac{\sqrt{3}}{4} \times a^2 \), where \( a \) is the length of a side? For your triangle with a side length of 8.9 cm, the area would be approximately 35.05 cm², making it a nice little space for all kinds of geometric explorations! In real-world applications, equilateral triangles are not just confined to geometry classes. They can be found in architecture, like in the design of trusses, where their shape provides amazing structural integrity. Plus, they're commonly seen in art and design, adding a touch of balance and symmetry to various creative projects!