Let $ABCD$ be a quadrilateral with $\angle A = \angle B = 90^o$, $AB = AD$. Denote $E$ as the midpoint of $AD$, suppose that $CD = BC + AD$, $AD > BC$. Prove that $\angle ADC = 2\angle ABE$.
Problem
Source: 2021 Saudi Arabia Training Lists p13 https://artofproblemsolving.com/community/c2758131_2021_saudi_arabia_training_tests
Tags: geometry, angles, equal angles
