Question

Use a paragraph proof to prove the corresponding angles postulate:

Given: segment A B is parallel to segment C D.

Prove: Corresponding angles are congruent

Answer 1

are you familiar with indirect proofs?

Answer 2

Not really. I hate them. :/

Answer 3

here this might help i have to go

Answer 4

Hmm... if you're familiar with indirect proofs (contradiction), maybe this will help:
http://jwilson.coe.uga.edu/MATH7200/Sect1.3.html
Starting at "To prove Thm 1.18 with an indirect proof ..."


Ill be back soon

Answer 5

Okay. Thanks.(:

Answer 6

Someone help?

Answer 7

One way you can go is this

If AB || CD, then by the same side interior angles theorem, angles 3 and 6 are supplementary, so

m < 3 + m < 6 = 180

angles 2 and 3 are a linear pair, so they are supplementary as well, ie

m < 2 + m < 3 = 180



Now if you look at the two equations below

m < 3 + m < 6 = 180
m < 2 + m < 3 = 180

you'll see that they both add to 180, so we can use substitution to get


m < 3 + m < 6 = m < 2 + m < 3

then we can subtract m < 3 from both sides (ie use the additive property of equality) to get m < 6 = m < 2

So this proves that the corresponding angles 2 and 6 are congruent. You can use these steps to prove other pairs of corresponding angles are congruent as well.

Answer 8

I'm still confused. O_o

Answer 9

where are you stuck?

Answer 10

The additive property of equality part.

Answer 11

the additive property of equality is this

if a = b

then we can add any number (positive or negative) to both sides to get

a+c = b+c

Answer 12

in this case, we're adding the negative version of angle 3 so we're effectively subtracting it from both sides really

Answer 13

But you said subtract, how is that additive?

Answer 14

adding a negative is the same as subtracting

Answer 15

ex: 1 + (-2) is the same as 1 - 2

Answer 16

you can use the subtraction property of equality, which says

if a = b, then a - c = b - c

if you're not sure about the additive property of equality

Answer 17

Okay.

Answer 18

either way, they basically say the same thing

Answer 19

Okay. Thank you.(:

Answer 20

you're welcome