which type of triangle must have perpendicular lines
Perpendicular The legs of a right triangle are perpendicular to each other.
Kite (geometry) If a kite is equiangular, meaning that all four of its angles are equal, then it must also be equilateral and thus a square. A kite with three equal 108° angles and one 36° angle forms the convex hull of the lute of Pythagoras.[1]