Initially I was of the opinion that if two diagonals in a parallelogram intersect then the angle formed at the point of intersection is 90 degrees (I came up with this conclusion by inserting values) , if this applied to a parallelogram then I assumed it also applied to a square or a rectangle.In both the figures below i assumed angles A , B , C will always be 90 degrees at least that's what I thought.Am i wrong ?
Now I just came across a question which is conflicting with this concept the question is:
ABCD is rectangle the diagonals AC and BD intersect at E (reflected in red figure) .Which of the statement is not necessarily true. The answer to this was : AE is perpendicular to BD. Could anyone let me know why is this not true ? Did i have the wrong idea to start with ?