ID: A
3 ANS:
To prove that ABCD is a parallelogram, show that both pairs of opposite sides of the parallelogram are parallel by
showing the opposite sides have the same slope:
A rectangle has four right angles. If ABCD is a rectangle, then
,
,
, and
. Lines
that are perpendicular have slopes that are the opposite and reciprocal of each other. Because
and
are not
opposite reciprocals, the consecutive sides of ABCD are not perpendicular, and ABCD is not a rectangle.
REF: 060633b
4 ANS:
. To prove that ABCD is a rhombus, show that all sides are congruent using the distance formula:
.
REF: 060327b
5 ANS:
,
,
,
(Definition of
slope).
,
(Parallel lines have equal slope). Quadrilateral ABCD is a parallelogram (Definition of
parallelogram).
,
(Definition of
distance).
is not congruent to
(Congruent lines have equal distance). ABCD is not a rhombus (A rhombus
has four equal sides).
REF: 061031b
2