Question

A = {Regular Polygons}, B = {Triangles} and C = {Quadrilaterals}. 

Find i) A ∩ B ii) A ∩ C iii) A – B iv) A – C

Answer 1

A = {Triangles, Quadrilaterals, Pentagon, Hexagon, Heptagon} 

B = {Triangles}; 

C = {Quadrilaterals} 

i) A ∩ B = {Triangles, Quadrilaterals, Pentagon, Hexagon, Heptagon} ∩ {Triangles} =  {Triangles}

ii) A ∩ C = {Triangles, Quadrilaterals, Pentagon, Hexagon, Heptagon} ∩ {Quadrilaterals} = {Quadrilaterals} 

iii) A-B = {Triangles, Quadrilaterals, Pentagon, Hexagon, Heptagon} – {Triangles} = {Quadrilaterals, Pentagon, Hexagon, Heptagon} 

iv) A – C = {Triangles, Quadrilaterals, Pentagon; Hexagon, Heptagon} – {Quadrilaterals} 

= {Triangles, Pentagon, Hexagon, Heptagon}