To calculate the area of a triangle, you can use the formula:
\[ \text{Area} = \frac{1}{2} \times \text{base} \times \text{height} \]
In this case, the base is 8 cm and the height is 5 cm. Plugging in these values:
\[ \text{Area} = \frac{1}{2} \times 8 , \text{cm} \times 5 , \text{cm} \]
\[ \text{Area} = \frac{1}{2} \times 40 , \text{cm}^2 \]
\[ \text{Area} = 20 , \text{cm}^2 \]
Therefore, the area of the triangle is \( 20 , \text{cm}^2 \).