The area of a triangle can be calculated using the formula:
\[ \text{Area} = \frac{1}{2} \times \text{base} \times \text{height} \]
In this case, the base of the triangle is 7.5 cm and the height is 4 cm.
Plugging in the values:
\[ \text{Area} = \frac{1}{2} \times 7.5 , \text{cm} \times 4 , \text{cm} \] \[ \text{Area} = \frac{1}{2} \times 30 , \text{cm}^2 \] \[ \text{Area} = 15 , \text{cm}^2 \]
The area of the box lid is 15 square centimeters.