Question 53
Let $A$, $B$, $C$ and $D$ be four different points lying on a common circle in this order. Assume that the line segment $AB$ is the (only) longest side of the inscribed quadrilateral $ABCD$.
Prove that the inequality
$$
AB + BD \gt AC + CD
$$
holds.
(Karl Czakler)
Prove that the inequality
$$
AB + BD \gt AC + CD
$$
holds.
(Karl Czakler)