- Four sides - Four angles - Four vertices  - The diagonals are equal in length and perpendicular and bisect each other.

 - Four sides  - Four angles  - Four vertices  - The diagonals are equal in length and not perpendicular and bisect each other.

 - Three sides  - Three angles  - Three vertices  - The sum of measures of the interior angles of any triangle = 180 ⁰

 - Isosceles triangle  - Equilateral triangle  - Scalene triangle

 - Acute angle  - Obtuse angle  - Right angle

 For any polygon  number of sides = number of vertices = number of angles

 put ( √ ) for the correct answer and put ( × ) for the incorrect answer.  ( 1 ) there can be two right angle in one triangle ( )  ( 2 ) there can be three acute angles in one triangle ( )  ( 3 ) in the rectangle every two opposite sides are equal in length ( )  ( 4 ) the diagonals of the square are not perpendicular ( )