Don’t lose your progress!

We cover every section of the GMAT with in-depth lessons, 5000+ practice questions and realistic practice tests.

Up to 90+ points GMAT score improvement guarantee

The best guarantee you’ll find

Our Premium and Ultimate plans guarantee up to 90+ points score increase or your money back.

Master each section of the test

Comprehensive GMAT prep

We cover every section of the GMAT with in-depth lessons, 5000+ practice questions and realistic practice tests.

Schedule-free studying

Learn on the go

Study whenever and wherever you want with our iOS and Android mobile apps.

The most effective way to study

Personalized GMAT prep, just for you!

Adaptive learning technology focuses on your academic weaknesses.

Quadrilaterals: Evolution

Diagonal $$BD$$ divides quadrilateral $$ABCD$$ into two triangles. Are these triangles congruent? >(1) $$AD \parallel BC$$ >(2) $$AB=CD$$
Correct! The issue here is whether quadrilateral $$ABCD$$ _must_ be divided into two congruent triangles by diagonal $$BD$$. By finding even one quadrilateral that cannot be divided into two congruent triangles, you have proved that both statements are insufficient. If both statements are true, then the quadrilateral is either an isosceles trapezoid (a trapezoid whose legs are of equal length) or a parallelogram. By definition, every parallelogram has congruent sides and therefore can be divided into 2 congruent triangles. However, an isosceles trapezoid meets conditions 1 and 2 but when divided by line $$BD$$, the resulting triangles are not congruent.
Incorrect. [[Snippet]]
Incorrect. [[Snippet]]
Incorrect. [[Snippet]]
Incorrect. [[Snippet]]
Statement (1) ALONE is sufficient, but Statement (2) alone is not sufficient to answer the question asked.
Statement (2) ALONE is sufficient, but Statement (1) alone is not sufficient to answer the question asked.
BOTH Statements (1) and (2) TOGETHER are sufficient to answer the question asked, but NEITHER statement ALONE is sufficient to answer the question asked.
EACH statement ALONE is sufficient to answer the question asked.
Statements (1) and (2) TOGETHER are NOT sufficient to answer the question asked, and additional data specific to the problem are needed.