Question

Amanda is writing a proof for the theorem stated below. Theorem: The sum of interior angles of a triangle is 180°. She first drew the figure shown below. Which theorem will she most likely use in the proof? Supplements of congruent angles are congruent. If two angles of a triangle are congruent, the sides opposite these are congruent. All straight angles are congruent. Corresponding angles formed by parallel lines and their transversal are congruent.

Answer 1

hint, definition of supplement is ? :)

Answer 2

two angles that add up to 180 degrees right?

Answer 3

http://learn.flvs.net/webdav/assessment_images/educator_geometry_v14/pool_Geom_3641_1000_Subtest_01_02/image0014e8c4bc3.jpg
here's the picture :)

Answer 4

yeah, exterial angle = the sum of the other 2 angles not adjacent to it :) sorry i can't see the picture

Answer 5

sorry...i'll try to get it

Answer 6

I think it's the first one??

Answer 7

i see, forget all others, start over :)
angle 1 equal because they are alternate interior of the 2 parallel line right..and the other one is?

Answer 8

The other angle?

Answer 9

your answer have transveral isn't it? :) ...was hoping you say that :)

Answer 10

Okay it's the last option because there is parallel lines and a transversal which cuts through those lines and that'd why angle 1 and angle 1 are congruent by alternate interior angles...am I right?? :)

Answer 11

I was going to say that...but I wasn't sure

Answer 12

:) yeah

Answer 13

yay!! Thanks!

Answer 14

after that, 1+2+3 = 180 right? :)

Answer 15

yes which makes sense