Take any quadrilateral such as ABCD above. Construct the midpoints of each side and join them to form another quadrilateral EFGH. Varignon's Theorem asserts that the ...

Therefore, we can also say a rectangle is a quadrilateral where opposite sides are equal with four right angles. Parallelogram. A parallelogram is a quadrilateral where opposite sides are parallel ...

Image caption, To do this, split the parallelogram into a right-angled triangle and a trapezium. A trapezium is a quadrilateral with one pair of parallel sides. Image caption, Move the right ...