Question

Proofs..

Answer 1

@jim_thompson5910 mind helping with one more? :/

Answer 2

what's your question?

Answer 3

oops wrong one

Answer 4

what's the reasoning for line 2? any idea?

Answer 5

No. I mean they are talking about one angle being equal to itself..

Answer 6

which property makes that true?

Answer 7

Angle of a triangle? :l I'm clueless

Answer 8

when you look into a mirror, you see your ______

Answer 9

REFLECTION

Answer 10

This is why I like your help. you make in understandable.

Answer 11

yep REFLEction

so the REFLExive property is why A = A is true. it's trivial and seems kinda stupid (of course something is equal to itself, how could it not?) but at the same time it's good to have a rigorous set of rules

Answer 12

see the first line
http://www.regentsprep.org/regents/math/geometry/gpb/theorems.htm

Answer 13

I feel like you have a folder of math websites. You have so many helpful ones o.o

Answer 14

sometimes, but others I google

Answer 15

and regents prep tends to pop up a lot (esp with geometry)

Answer 16

ahh.

Answer 17

So what about the last line?

Answer 18

Corresponding sides?

Answer 19

I'm checking your line 3 and line 4

Answer 20

alright

Answer 21

from this link we visited earlier

http://www.regentsprep.org/regents/math/geometry/gp11/LsimilarProof.htm

I'm going to focus on the SAS similarity theorem. See attached

Answer 22

That theorem says if you have a pair of corresponding congruent angles, and you have that proportion mentioned in the attachment, then the triangles are similar

Answer 23

okay

Answer 24

was one of the lines wrong or are we on the last line?

Answer 25

so that's the reason for line 3.

Answer 26

we only use the AA theorem IF we had 2 congruent corresponding angles. We had that last time, but we don't have that this time

Answer 27

oh..

Answer 28

so would it be sas?

Answer 29

SAS similarity theorem, yes

Answer 30

is the fourth line okay?

Answer 31

no, but luckily you might know the theorem

Answer 32

you mentioned the AA theorem. What exactly does the AA theorem say?

Answer 33

AA? xD

Answer 34

Angle Angle

Answer 35

specifically what does the entire theorem say? (other than just Angle Angle)

Answer 36

To show two triangles are similar, it is sufficient to show that two angles of one triangle are congruent (equal) to two angles of the other triangle.

Theorem:

If two angles of one triangle are congruent to two angles of another triangle, the triangles are similar.

Answer 37

So

IF the angles are congruent
THEN the triangles are similar

flip that around to say...

IF the triangles are similar
THEN the angles are congruent

Answer 38

the theorem you wrote out is the original AA similarity theorem

the flipped version is the converse of that said theorem

Answer 39

Alright.. so would it be a converse
AA theorem?

Answer 40

converse of the AA similarity theorem, yep

Answer 41

And then the last line

Answer 42

any ideas?

Answer 43

Parallel lines?

Answer 44

well that's what you want to prove

Answer 45

how can you use the previous line?

Answer 46

https://www.mathsisfun.com/geometry/parallel-lines.html

Answer 47

I dont understand how to use the line before

Answer 48

Traversal something?

Answer 49

this might be of better help

http://www.nhvweb.net/nhhs/math/mschuetz/files/2012/11/Section-3-3-2012-2013.pdf

Answer 50

Which one :/

Answer 51

first page

Answer 52

Corresponding angles?

Answer 53

the converse of the corresponding angles theorem

Answer 54

Once again thank you!

Answer 55

np