Final answer:
The shape of a pennant is typically an elongated isosceles triangle, used for celebratory or communication purposes in sports and nautical settings.
Step-by-step explanation:
The shape of a pennant is most commonly a tapered, elongated isosceles triangle where the shortest edge is connected to a mast or pole. Pennants have been traditionally used in various contexts such as sports, where teams use them to celebrate achievements, or in nautical settings, where they signal information between ships. The conventional shape of a pennant is a triangle extrapolated into a more elongated form rather than being perfectly equilateral or right-angled.