Question 2 by Shamus Seng:
The correct answer is D, which consists of A, B, and C.
A square, together with a rhombus, kite, trapezium, and rectangle, is a four sided figure, just like the parallelogram. It has two pairs of parallel sides, and the four angles within add up to 360°.
The opposite sides of the square and parallelogram are parallel because the opposite angles are equal as well. If one of the sides were extended longer, the adjacent side will not be parallel to its opposite side, therefore opposite sides the square and parallelogram must be parallel.
There is only one pair of parallel sides in a trapezoid, because only one pair of adjacent angles form 180°
All of the above.
Question 4 by Shamus Seng :
No, I do not agree with the statement that all parallelograms are squares. Some parallelograms are slanted to one side, which means not all four sides of the parallelogram have the same length. A square is a shape with all four sides of the same length. Furthermore, the angles of the parallelogram are of different values, although the opposite angles are of the same value. A square is a shape with all four angles having the same value. Therefore, not all parallelograms are squares.
Question 5 by Shamus Seng :
If we abstract BFDE from ABCD, we can see clearly that it is a parallelogram, because it possesses three important points that all parallelograms have. Firstly, it has two pairs of parallel sides. Secondly, its opposite sides are parallel. Lastly, its opposite angles are of the same value. Hence I conclude that BFDE is a parallelogram.