E / C
Q1.
AB=AC, BD=CD
-> ABC, DBC are isosceles triangles respectively.
-> Angle ABD = Angle ACD
-> Triangle ABD = Triangle ACD
-> Angle BAD = Angle CAD
-> BC is perpendicular to AD (because Triangle ABC is isosceles.)
-> Triangel ABE=ACE, DBE=BCE,
and Angle AEB=AEC=DEB=DEC=90
A. BE=EC <- true, Triangel AEB=AEC
B. AD is perpendicular to BC <- true
C. Triangel BDE=CDE <- true
D. Angle ABD=ACD <- true
E. all true <- true
answer : E
Q2.
Rect.ABCD -> AB=CD, AD=BC,
and, according to the symmetricalness of rect., AE=BE=CE=DE
-> tri. AEB=CED : isosceles,
tri. BEC=AED : isosceles.
A. AE=BE <- true
B. ang. AEB=CED <- true; vertical angles.
C. AE perpend. BD <- not necessarilly; true only when the rect. is a square.
D. tri. AED and AEB are equal in area <- true; these 2 triangles are 2 parts of tri. ABD. When you assume BE and DE are the bases of each tri., they are sharing the height. So, they have the same height and the same length of the base, and thus the same area.
E. ang. BAC=BDC <- true; tri. EAB=EDC.
answer : C