To solve this, I need to understand what the terms represent. Based on the provided notation, this problem appears related to structural engineering, particularly concerning an I-beam or similar cross-section. Here's how these terms are typically defined:

1. D = Depth or height of the beam (300 mm)
2. BF = Width of the flange (200 mm)
3. TF = Thickness of the flange (20 mm)
4. TW = Thickness of the web (25 mm)

These parameters are often used to calculate the moment of inertia (I) or the section modulus (S) of the beam, which are critical for understanding the beam's strength and how it will behave under load.

Would you like me to calculate the moment of inertia and section modulus, or is there another specific calculation or analysis you need based on these dimensions?

Let me know, or provide more details if needed!