Circle question (1 Viewer)

[Fortian09]

a) In triangles XAC and XDB:
Angle X is common
Angle XAC = BDX (exterior angle of cyclic quad)
Angle XCA = XBD ( '' '' '' '' '' )
therefore, XAC and XDB are congurent (AAA)

b) Can't remember the exact name of the rule, but it's something like lines from exterior point...bleh, I can't remember it. But it's a circle geometry rule

c) Using the given formula
XA*XB = XC*XD
4*9 = x*(x+9)
x^2 + 9x = 36
x^2 + 9x - 36 = 0
(x-3)(x+12) =0 (x>0)
x = 3

Can someone work B out please?

 

[lyounamu]

Can someone work B out please?

triangle XAB lll triangle XDB,

XA/XD = XC/XB (sides are in equal ratio of similar triangles)

So XA . XB = XC . XD

 

[tommykins]

Yeah, Sam did his two hsc exams last year. (lucky bastard)

Wow, fucking tank.

 

[Fortian09]

LOL why do u guys all have to be so smart?
what school do u guys go to?

 

[lyounamu]

LOL why do u guys all have to be so smart?
what school do u guys go to?

who are you referring to?

Aerath = Sydney Boys High School
I = St Pius X College
lsam = Knox Grammar
lolokay= ????
ronnkee = homebush boys
bored of sc =???
JSB (whatever) = ???
ShaonO = Patrician's brothers college Blacktown

I guess I am the dumbest of all...

 

[Fortian09]

why do i have to be so stupid

 

[Fortian09]

and yet ur so smart,
its not the school that counts its u

 

[Fortian09]

more....
I'm srsly starting to feel stupid

 

[lolokay]

why do i have to be so stupid

[O is the centre]
AOC = 2.ADC (angle at centre is twice angle at circumference)
ADC + ABC = 180 (cyclic quad)
ABC + CBP = 180
2.CBP = 2.ADC = AOC

*and for b) it's just cointerior angles on parallel lines

 

[lolokay]

more....
I'm srsly starting to feel stupid

basically just remember that the opposite angles of a cyclic quad' add to 180, and that the triangle made by two points between them is isosceles.
for c)BRQ you have to use the rule that the angle from two points to the centre is twice the angle from two points to the circumference

 

[Aerath]

Wow, fucking tank.

Yeah, smart kid. Shame he's too arrogant.

I guess I am the dumbest of all...

You work harder than all of us. Combined.

LOL why do u guys all have to be so smart?
what school do u guys go to?

You know, Fort Street students in our grade are really smart. Namely, Adrian Lim.

 

[Fortian09]

Lol does everyone know Adrian lim?
he came from Christian brothers though
ahh welllz

 

[lyounamu]

Yeah, smart kid. Shame he's too arrogant.

Yeah, he does have that tendency. (no offence to you sam, you admitted)

 

[Aerath]

Lol does everyone know Adrian lim?
he came from Christian brothers though
ahh welllz

Well, he still kicked ass in Chemistry and PD/H/PE. And came Top 5 for Maths. And Physics.

 

[lyounamu]

Well, he still kicked ass in Chemistry and PD/H/PE. And came Top 5 for Maths. And Physics.

PD/H/PE in Sydney Boys?

Rather surprised.

 

[Aerath]

PD/H/PE in Sydney Boys?

Rather surprised.

Erm, this Adrian Lim guy goes to Fort Street. But we have PD/H/PE at SBHS. What's so surprising about that? Most schools do.

 

[lyounamu]

Erm, this Adrian Lim guy goes to Fort Street. But we have PD/H/PE at SBHS. What's so surprising about that? Most schools do.

I was expecting all those top Selective Schools to have all the high scaling subjects. I know that James Ruse doesn't have Legal Studies and certain subjects.

 

[u-borat]

a lot of top schools also don't have latin, which scales like a bitch.

 

[lyounamu]

a lot of top schools also don't have latin, which scales like a bitch.

"bitch" as in extremely high?

 

[Aerath]

"bitch" as in extremely high?

Yes.