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 triangles are similar, if their corresponding angles are .......... (proportional, equal)
(v) Two triangles are similar, if their corresponding sides are ........... (proportional, equal)
(vi) Two polygons of the same number of sides are similar, if (a) their corresponding angles are and (b) their corresponding sides are ...........(equal, proportional).
(i) Since all circles have centre and circumference, therefore all circles are similar.
Hence Similar
(ii) Since all squares have each angle $90^{\circ}$ and sides are proportional, therefore all squares are similar.
Hence Similar
(iii) In equilateral triangle each angle is $60^{\circ}$ therefore all equilateral triangles are similar.
Hence equilateral
(iv) Two triangles are similar, if their corresponding angles are equal.
(v) Two triangles are similar, if their corresponding sides are Proportional.
(vi) Two polygons of same number of sides are similar, if (a) their corresponding angles are equal and (b) their corresponding sides are Proportional.