arc acute alternate angles arrowhead arc bisector chord circle circular circumference concave concentric cone congruent convex corresponding angles cube cuboid curved cyclic quadrilateral cylinder diagonal line diameter dice edge enlargement equidistant equilateral exterior angle face heptagon hexagon hexagonal horizontal identical interior angle intersection isosceles kite locus midpoint net oblong obtuse octagon octagonal parallel parallelogram pentagon pentagonal perpendicular polygon prism pyramid quadrilateral radius rectangle rectangular reflection reflex regular rhombus right angle rotation scalene sector segment semi-circle side sphere square star straight tangent tetrahedron translation trapezium triangle triangular vector vertex vertices vertical vertically opposite angles