## estudier 3 years ago Side length of equilateral triangle? (I have to draw it)

1. estudier

|dw:1350739907443:dw|

2. sauravshakya

U mean length of BC

3. estudier

yes, ABC is equilateral so any side...

4. sara12345

4/sqrt(3) ?

5. estudier

Sorry, try again...

6. sara12345

4 + 2/sqrt(3)

7. estudier

Um...no.

8. sara12345

|dw:1350740356848:dw|

9. sara12345

|dw:1350740418399:dw|

10. sara12345

|dw:1350740461276:dw|

11. estudier

How u get 30?

12. estudier

Hint - make a transformation

13. sara12345

i wasnt thinkin g sorry.. .let me think

14. estudier

U didn't like my hint?

15. estudier

No!

16. estudier

Imagine that the slant line is the x-axis and shift the triangle "up" 2 so that A is at the origin. Now try it...

17. sara12345

trying

18. estudier

U see what I mean? Now if you drop the perpendiculars from B and C, they will 5 and 4

19. sara12345

dont post any more hints.. plz

20. estudier

|dw:1350742011463:dw|

21. Kashan

4 sqrt 2

22. estudier

Nope, sorry.

23. estudier

I'm getting worried now, I better check my answer... This is Pythagorus and some algebra, right?

24. sara12345

im getting 3 quadratics wid 3 variables

25. sauravshakya

|dw:1350743128666:dw|

26. sauravshakya

I guess Now, using cosine rule and sine rule will give x and y.

27. estudier

|dw:1350743084775:dw|

28. sauravshakya

is it 6.4291 ?

29. estudier

I have 2 sqrt 7

30. estudier

First 2 equations give s^2-t^2 = 9 Second and third give s^2 -2st =24 t = (s^2-24)/2s substitute in s^2-t^2 gives a quadratic in s etc.

31. estudier

I think Sara was closest...

32. sauravshakya

33. sauravshakya

Where did I go wrong???

34. estudier

I will have a look later on.....

35. sauravshakya

okay!

36. sauravshakya

Thanx @shubhamsrg AND yes there was a mistake in cosine law. Now, that gives the length 5.2915

37. sauravshakya

Which looks correct.

38. shubhamsrg

you did all the work buddy,, as i said,,a human error..i do more mistakes than that in my work.,, anyways,,good job YET AGAIN>>

39. estudier

Ah, u found it, good:-)