Given data :
AD=BC
BC is perpendicular to AE
AD is perprndicular to BE
In the given Figure,
BC is perpendicular to AE so, angle BCE =90 degree
Similarly, AD is perprndicular to BE so, angle ADE = 90 degree
And in the triangle ADE and BCE,
angle E is common in both triangles
Since, AD=BC given
So,
[tex]\begin{gathered} \angle D=\angle C\text{ (Right angle=90)} \\ \angle E=\angle E(Common) \\ AD=BC\text{ (Given)} \\ \text{ So, by Angle Angle Side congurency property,} \\ \Delta ADE\cong\Delta BCE \end{gathered}[/tex]From the property of congurency,(CPCT) all the corresponding sides and angles of congurent triangles are equal so,
[tex]\angle A=\angle B\text{ (CPCT)}[/tex]