## eroshea 3 years ago Find the volume of a regular tetrahedron whose altitude measures 10 cm.

1. hartnn

the formula is V = $$\sqrt 2$$/12 * a^3

2. eroshea

it is not the edge that is given but the ALTITUDE..

3. eroshea

now i got it.. :))

4. Miyuru

How ?

5. eroshea

altitude = root(2/3) * a 10 = root(2/3) * a 100=2/3 a^2 a= 5 root 6 V = root(2)/12 * a^3 V = 216.5

6. Miyuru

I thought it like this..$\large\color{green}{x=\frac{100}{\sqrt{3}}}$ |dw:1353600894733:dw|

7. Miyuru

Sorry..$\large\color{green}{x=\frac{10}{\sqrt{3}}}$

8. eroshea

that's fine.. ^^

9. Miyuru

;)

10. Miyuru

@eroshea I am glad tht u got it..:D :)

11. eroshea

thanks for your help @hartnn and @Miyuru ^^

12. Miyuru

I didn't help.. o.O

13. Miyuru

Thank @hartnn ONLY

14. eroshea

well, you tried helping me.. so thanks :))

15. hartnn

u got it on your own, @eroshea :)

16. Miyuru

Is my way wrong @hartnn

17. hartnn

if u got the same volume, then u are correct.

18. Miyuru

It's nearly 181.4 :(

19. hartnn

then incorrect :P

20. Miyuru

:D

21. eroshea

:D

22. Miyuru

OHH Anyway thnks for U all and Welcome...

23. Miyuru

Ohh @eroshea you mean the height is 10.. Isn't it ?

24. eroshea

yes

25. Miyuru

I thought it was the altitude of a triangle.. :P

26. eroshea

no.. it's the height of the tetrahedron

27. Miyuru

Ok got it.. :) Then your way is correct. :D

28. eroshea

yep :D

29. kneenutskii

what is the figure and where did 2/3 came from?