Fill in the blanks using the correct word given in brackets:

           (i)   All circles are __________. (congruent, similar)

           (ii)  All squares are ___________. (similar, congruent)

           (iii) All ____________ triangles are similar. (isosceles, equilateral)

           (iv) Two polygons of the same number of sides are similar, if (a) their corresponding angles are _________ and (b) their corresponding sides are ___________. (equal, proportional)