trigon, trilateral, triangular, equilateral, rectangle, trapezoid, triangled, hexagon, scalene, parallelogram, more...

square, circle, rectangle, oval, polygon

equilateral, isosceles, scalene, right, acute, obtuse, degenerate, triangular pyramid, more...

equilateral, right, isosceles, angled, spherical, small, posterior, red, black, inverted, anterior

triangular shape,   three angles,   trig figure,   three sided shape,   three point,   triangular piece