24yup[3][3]
26 Answers
62One more thing...
Why do you have to make things more complicated by taking root 2 in the calcualtion?
it was better the way sky did first.. take (6,6,0) etc
and then divide by root 2 if you are finding lengths. or divide by 2 if you are finding areas :)
good luck :)
24@ sky..........i didnt said about ur typing mistake......
i was replying to post #15 of deepanshul about my soln...........[1][1]
1perfect .. now just waiting for someone to calculate .. vectorially ... just proceeding eureka's method .. or something else ..
1no no dont apologise//
and yes eureka.. it WAS NOT a typo...
yeh bhi galati hi tha...
main nahi dekhi thi...
too stupid a work for a <one-month jee-aspirant ......
am sorry...
1oho bhaiya .. got it .. sorry sky .. i apologise .. ur method is the best ....
62deepanshu and Ankit.. skky is correct this time
see carefully
each side length is 6 root 2
Only thing she has to do is divide the final answer by root 2 :)
1bhaiya sky ka post check toh kijiye .. she is still incorrect ..
1sorry....
mera yeh galti karne kii adat ni jaegi ... [2]
the points are A(0,0,0) , B(6,0,6), C(0,6,6) and D(6,6,0).
i think this way calculation is simple...
24taking A as origin
B=b,C=c,D=d
=>E=c/3 and F=b+2c/3
now write EF and FD and take cross product
62yes ankit.. perfect :)
That is why i was saying to look at the 3 triangles seperately :)
1Nishant bahiya .. a simple approach(but bulky process) just struck me
EF2 = EC2 + CF2 - 2EC.CF cos60°
so we get the value of EF
Similarly we can find ED and DF
Then we can use Heron's formula to calculate the area ...
1well we can take points...
A(0,0,0) , B(0,6,0), C(0,0,6) and D(6,0,0).
now the point E is 0,0,2
and point F is 0,2,4 .
now find area..........
1DF2 +FC2=DC2
DF2=36-9=27 ( FC= 3 units)
DF=√27
dont know what to do further
trying to think
1
regular tetrahedron with each side = 6 units
AE : EC = CF : FB = 1:2
find the area of triangle DEF ....