You're likely thinking of Trivial Pursuit. Its iconic board is a six-spoked wheel where each wedge is a triangle representing a category:
Players move around the circular track, earn "cheese" wedges by answering correctly in each category, then race to the center for the final question.
Other triangular-board games exist (e.g., Chinese Checkers star, Blokus Trigon), but Trivial Pursuit is the classic "pie/wedge" triangle board.