The figure below shows PQ and RS as parallel lines cut by the transversal XY.

Which fact is used to prove that angles QMN and MNR are congruent?

If a transversal intersects two parallel lines, the alternate interior angles are equal.

If two parallel lines are cut by a transversal, the sum of the complementary angles is 180˚.

If a transversal intersects two parallel lines, the vertical angles are supplementary.

If two parallel lines are cut by a transversal, the sum of the alternate exterior angles 180˚.

Question

The figure below shows PQ and RS as parallel lines cut by the transversal XY.
 

 
Which fact is used to prove that angles QMN and MNR are congruent?

 If a transversal intersects two parallel lines, the alternate interior angles are equal.

 If two parallel lines are cut by a transversal, the sum of the complementary angles is 180˚.

 If a transversal intersects two parallel lines, the vertical angles are supplementary.

 If two parallel lines are cut by a transversal, the sum of the alternate exterior angles 180˚.

anonymous · Answer

can you hel pme out im not sure if its the third one

ganeshie8 · Answer

If a transversal intersects two parallel lines, the alternate interior angles are equal.

all other options make no sense.

anonymous · Answer

http://learn.flvs.net/webdav/assessment_images/educator_geometry_v14/pool_Geom_3641_0900_Subtest_03_13/image0044e734d45.jpg

anonymous · Answer

thats for the image

ganeshie8 · Answer

the link is not working, but the thing is when two lines are parallel, and a line cuts them. il draw a pic wait

ganeshie8 · Answer

|dw:1347826329550:dw|

ganeshie8 · Answer

those are the two parallel lines ok

ganeshie8 · Answer

lets draw a transveral that cuts both the lines

ganeshie8 · Answer

|dw:1347826378444:dw|

ganeshie8 · Answer

thats the setup.

ganeshie8 · Answer

then, alternate interior angles are equal.

ganeshie8 · Answer

|dw:1347826412648:dw|