Just ask me.

Solution: let AB be X.

Then OA= root number 2/2x

Square of the root number 2/2x = square of x.

So, the square of AO+the square of bo = the square of ab.

Angle AOB=90 degrees

Therefore, four is not a square like ABCD.

(Diagonal lines are equally divided. A vertical and equal quadrilateral is a square)

Due to limited typing, special symbols can't be typed. Please forgive me! )

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