Question

Please help me with this

Answer 1

hmm.... i think this is what u have to do...
first consider the parallelogram ABCD

now construct the diagonal AC
after that you will get 2 triangles as ABC and ADC
now u have to prove that these 2 triangles are congruent ..
to prove that u can use the case SSS ( congruence by side - side - side )
first u have to do that .. can u do it ?

and for that i assume that wehave to use the fact that the opposite sides of a parallelogram are equal in length.Since the question asks to prove that opposite angles are equal ..i think there is no problem in using the above fact..

Answer 2

How do I prove the SSS postulate?

Answer 3

consider the triangle ABC & triangle ADC
AB = AC ( opposite sides of a parallelogram)
AD = BC ( Opposite sides of a parallelogram)
AC = AC ( diagonal )
so..
triangle ABC & triangle ADC r congruent (SSS)

got it ?

Answer 4

Okay I got it, I do have a question though

Answer 5

Is an indirect proof the same as writing like a two column proof

Answer 6

hmmm.. a proof can be done in 2 ways as far as i know.. in a paragraph or in a 2 column ... and paragraph is the two column proof written in sentences.. wt ive given u is the way how to prove it.. writing it using one of the any type is ur work.. if u prefer to use the 2 column proof.. its ur choice. but u do need to write wt ive show u in a proper method.. can u do it using the 2 column proof ?

Answer 7

I don't know

Answer 8

ok...


is it clear ?

Answer 9

now ..if its clear to u... then we are done proving that 2 triangles are congruent

now considering the 2 congruent triangles..
triangle ABC and triangle ADC
angle ABC = angle ADC ( corresponding angles of congruent triangles)--- (1)
and
angle CAB= angle ACD ( corresponding angles of congruent triangles) --- (2)
angle CAD = angle ACB( corresponding angles of congruent triangles) ---(3)
(2) + (3)
angle CAB + angle CAD = angle ACD + angle ACB
angle DAC = angle DCB ---- (4)

from (3) and (4) you have indirectly proved that opposite angles of a parallelogram are equal..
now u have to insert this to your previous 2 column proof and finished your work..
can you do it ? :)