diebeatsthegmat wrote:Is there a diagonal in quadrilateral ABCD that is also a bisector in ABCD?
(1) ABCD is a parallelogram.
(2) The diagonals of ABCD intersect at right angles

[spoiler]why the answer is C instead of D?
as i know a bisectore in ABCD will divide ABCD into 2 equal triangles, right? so A is also sufficient... ???[/spoiler]

diebeatsthegmat wrote:Is there a diagonal in quadrilateral ABCD that is also a bisector in ABCD?
(1) ABCD is a parallelogram.
(2) The diagonals of ABCD intersect at right angles

[spoiler]why the answer is C instead of D?
as i know a bisectore in ABCD will divide ABCD into 2 equal triangles, right? so A is also sufficient... ???[/spoiler]

goyalsau wrote:

diebeatsthegmat wrote:Is there a diagonal in quadrilateral ABCD that is also a bisector in ABCD?
(1) ABCD is a parallelogram.
(2) The diagonals of ABCD intersect at right angles

[spoiler]why the answer is C instead of D?
as i know a bisectore in ABCD will divide ABCD into 2 equal triangles, right? so A is also sufficient... ???[/spoiler]

HI! Buddy,

As i understand from your question, It ask whether Diagonal Divided the Quadrilateral in two equal part or not. ????

(1)
In Parallelogram diagonals divides the Parallelogram in to two congruent Triangles,

Hence Sufficient

(2) It simply Says Quadrilateral in a Rhombus...

Sufficient

I did some search on the net before posting this answer. and if somebody do not agree to me Please Share your source of reasoning......... I will be very Pleased...... I till be a new learning for me.........

diebeatsthegmat wrote:

goyalsau wrote:

diebeatsthegmat wrote:

I did some search on the net before posting this answer. and if somebody do not agree to me Please Share your source of reasoning......... I will be very Pleased...... I till be a new learning for me.........

i thought the same as you did and got the answer D but its C the OA. thats why i need an explanation why

https://www.merriam-webster.com/dictionary/bisector

According to webster, a bisector halves a line segment or angle, not a full figure. Here, the problem asks whether the line bisects the angles of the quadrilateral.

stat. (1): a diagonal will not bisect the angles of a regular parallelogram, but it will for a rhmbus, which is a specific case of a parallelogram. Insufficient, since we don't know either way.

Stat. (2): Without stat. (1), it is also possible to construct an equilateral trapezoid with perpendicular angles, for which the diagonals will not bisect the angles. Insufficient

combined : a parallelogram with perpendicular diagonals is a rhombus, in which the diagonals are also bisectors of the angles. Sufficient.

Geva@MasterGMAT wrote:

diebeatsthegmat wrote:

goyalsau wrote:

diebeatsthegmat wrote:

I did some search on the net before posting this answer. and if somebody do not agree to me Please Share your source of reasoning......... I will be very Pleased...... I till be a new learning for me.........

i thought the same as you did and got the answer D but its C the OA. thats why i need an explanation why

https://www.merriam-webster.com/dictionary/bisector

According to webster, a bisector halves a line segment or angle, not a full figure. Here, the problem asks whether the line bisects the angles of the quadrilateral.

stat. (1): a diagonal will not bisect the angles of a regular parallelogram, but it will for a rhmbus, which is a specific case of a parallelogram. Insufficient, since we don't know either way.

Stat. (2): Without stat. (1), it is also possible to construct an equilateral trapezoid with perpendicular angles, for which the diagonals will not bisect the angles. Insufficient

combined : a parallelogram with perpendicular diagonals is a rhombus, in which the diagonals are also bisectors of the angles. Sufficient.

thanks. i forgot about an equilateral