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 __________