## vmathhelp Group Title Can someone help me with Geo Problem! Diagonal AC divides a trapezoid ABCD two similar triangles ABC and ACD. Find AC if BC=4cm and AD=9cm one year ago one year ago

1. vmathhelp Group Title

@ganeshie8 I need help

2. vmathhelp Group Title

@ghazi @lalaly @AccessDenied

3. kajolc.2496 Group Title

Are these triangles similar by area?

4. kajolc.2496 Group Title

Is not there any fig. for this?

5. campbell_st Group Title

I think it looks like this|dw:1356206771435:dw| the angles marked x are equal by alternate angles in parallel lines

6. ghazi Group Title

|dw:1356207039082:dw|

7. vmathhelp Group Title

Now what do i do?

8. ghazi Group Title

have you provided whole information?

9. vmathhelp Group Title

yes

10. kajolc.2496 Group Title

I think there is something we r missing..

11. campbell_st Group Title

well the corresponding sides in the triangles are triangle ABC and triangle ACD are AB AC AB DC BC AD now you need to use the ratio's of corresponding sides in similar triangles

12. kajolc.2496 Group Title

but ques. does'nt say that it divides the triangles in equal areas!

13. kajolc.2496 Group Title

that's wat i was confirming earlier

14. vmathhelp Group Title

15. kajolc.2496 Group Title

SIMILARITY CAN ONLY BE USED WHEN AREAS ARE EQUAL

16. campbell_st Group Title

oops corresponding side should be AC and DC so using the ratio of corresponding sides $\frac{4}{9} = \frac{AB}{AC}= \frac{AC}{ DC}$

17. vmathhelp Group Title

what happens next?

18. vmathhelp Group Title

@campbell_st

19. campbell_st Group Title

who knows.... it doesn't make sense to me... there seems to be something missing from the question.

20. campbell_st Group Title

Oh, and triangles can be similar and have different areas the ratio will be the linear ratio squared. so the ratio of areas in the triangles is ABC:ACD = (4/9)^2

21. vmathhelp Group Title

@ghazi is there missing info?

22. ghazi Group Title

i am confused

23. vmathhelp Group Title