help, help I cannot think! (1 Viewer)

[farngarloc]

Help me. I feeling useless!!

two circles intersect at A and B. The tangent to the first circle at A cuts the second circle and D and the tangent to the second circle at B cuts the first circle at C. Prove that AC and DB are parallel.

Thanks for the help!

 

[cwag]

for my solution i drew two circles side by side, the left circle slightly smaller than right cirlce, with the top intersection labelled A and bottom intersection labelled B. The tangent at A from circle on left met the adjacent cirlce at D. The tangent at point B from circle of right met the other circle at point C. Sorry if u can't visulaise this......but for your proof..

Producue DA to a point E. Produce CA to a point F
Let < ADB = a
therefore < ABC = a ( angle in alternate segment)
< CAE = a ( angle in alternate segment)
< FAD = a ( vertically opposite angles)
therefore CA//BD (alternate angles < FAD and < BDA are equal)

 

[teddybear12]

lol..i try to post my answer but everytime i post it , some part of my answer goes missing =/

 

[cwag]

lol..i try to post my answer on but everytimei post it , some part of my answer goes missing =/

whenever u have a < followed by somthing without spacing it, it will not show.

 

[teddybear12]

this is my solution..i am guessing it's abt 60% rite? lol
ok, first u draw two circle as told in the question.
and draw straight line thrugh point A and B
draw another tangent at point B and name the point where that tangent and line AD meets, F
and draw line BC extensively then put another point at opposite side of C, call it H
let - line AB = T
line DB = G
< DAB = a

< DAB = < ACB = a ( Angle between chord and tangent is equal to internal opposite angle)
< ABF = a ( same as above)


< DBH = a ( Angle between chord and tangent is equal to internal opposite angle)

therefore, AC and DB is parallel ( corrsponding angles)


It looks so confusing and long X.x .. it would be so easier if i could draw it lol
please write something if there's problem with my answer ~_~

 

[teddybear12]

whenever u have a < followed by somthing without spacing it, it will not show.

lol thx....

 

[cwag]

...therefore line AB and CB are parallel

fine except for this....AB is not // to CB

 

[teddybear12]

fine except for this....AB is not // to CB

lol..yeah..true..no idea y i put it there..