- Consider a quadrilateral ABCD such that ∠BAD and ∠ADC are
perpendicular, the rays AB and CD are on the same side of the line
AD, and AB ≅ CD.
Prove the following claims on E2, H2, and
S2.
- ∠ABC ≅ ∠DCB.
- the perpendicular bisector of AD is also the perpendicular
bisector of BC.
Hint: Look for symmetries.