just wondering (1 Viewer)

[maths lover]

today in my extension test we had a circle geometry, quite a tough one which involved proving a quadilateral to be cyclic. well i didnt know how to do, so i decided to take a risk. and said if it was a cyclic quad then opps angles where supp and it worked then i said therfore it is cyclic, just wanted to know if you can do this to assume then prove.

 

[thoth1]

today in my extension test we had a circle geometry, quite a tough one which involved proving a quadilateral to be cyclic. well i didnt know how to do, so i decided to take a risk. and said if it was a cyclic quad then opps angles where supp and it worked then i said therfore it is cyclic, just wanted to know if you can do this to assume then prove.

that shuld be alrite.

 

[maths lover]

that shuld be alrite.

im praying so, it was a three marker so if i get it i will be a very happy man.

 

[tambam]

im praying so, it was a three marker so if i get it i will be a very happy man.

Yes, if opposite angles of a quadrilateral are supplementary, then you can assume it is a cyclic quad.

 

[thoth1]

im praying so, it was a three marker so if i get it i will be a very happy man.

hope so.

 

[maths lover]

Yes, if opposite angles of a quadrilateral are supplementary, then you can assume it is a cyclic quad.

,
no but mine was kinda like a proof by an assumption, i firstly assumed that it was a cycli quad and then found that they were supplementary concluded that it must be cyclic.

 

[maths lover]

,
You'll be a happy man.

so you think my method is valid.

 

[Drongoski]

Post the question. Did you show opp angles of the quadrilateral supplementary?

 

[maths lover]

idk the question since it was in my test. but in short terms as i just showed that one of the exterior angles of the quad was x. i then showed that the interior angle one right next to it 180-x since they are supp. then i said if it was a cyclic quad then the opp interior angle will be equal to x. but the opposite interior angles are supp and therfore it must be a cyclic quad do you understand?.