A cyclic quadrilateral $ABCD$ has sides of magnitude $1,2,3,4$ respectively. One of its diagonals is $2.5$. Find the magnitude of the other diagonal.
This is how I tried to solve it:
For a cyclic quadrilateral,using
$ac+bd=mn$ where $a,b,c,d$ are the magnitude of sides respectively and $m,n$ are diagonals.
$AB\cdot CD+BC\cdot DA=AC\cdot BD$ (Here I don't know what is $2.5$ whether its $AC$ or $BC$). however the other diagonal is found to be $4.4$
Is my solution correct?
What values should I assign to $AC$ and $BD$?