Final answer:
A flat-roofed, rectangular building with sloping sides is commonly known as a long house. Long houses were traditionally built by various cultures around the world and had sharply pitched roofs that resembled inverted boats.
Step-by-step explanation:
A flat-roofed, rectangular building with sloping sides is commonly known as a long house. Long houses were traditionally built by various cultures around the world and had sharply pitched roofs that resembled inverted boats. The sloping sides of the roof allowed snow to fall to the ground without causing collapse.