# The Science of Moving House: Pythagorean Theorem in Practice
Moving house is not just a physical challenge — it is a complex geometric puzzle. The apparent space of a room or lift deceives the human eye, especially when we ignore the third dimension. Applied mathematics can save you hundreds of pounds in returns and failed deliveries.# The 3D Diagonal Trick
The Golden Rule of Measuring
Never just measure the furniture. Always measure the critical access points: the clear width of the door frame (subtract door thickness if it does not open 180°), the lowest point of the ceiling on the landing, and the actual depth of the lift with doors closed. The formula d = √(w² + h² + z²) reveals whether the piece fits when tilted.
# The Moving Sofa Problem
Safety Margin Matters
A common mistake is assuming that if the furniture measures 80cm and the gap is 80cm, it will pass. It will not. The movers' hands, fabric elasticity and wall imperfections all require a minimum clearance of 2 to 5 cm. Without this margin, the piece will be scratched or wedged in by pressure.
Disassemble to Win
Before giving up because a piece does not fit, check the legs. Removing sofa legs often reduces the critical height by 10 to 15cm — the difference between success and leaving it in the lobby. Fridge doors and wardrobe handles also add critical centimetres.