| T O P I C R E V I E W |
| raghu |
Posted - 04/01/2008 : 13:14:29
there is a cube. Two diagonals from the same vertex are drawn, one as face diagonal and the other as space diagonal. Find the measure of angle between the two diagonals.
This is how I started .
I assumed a 1X1x1 cube. face diagonal came out as sqrt(2) and Space Diagonal came out as sqrt(3). I tried to apply sine rule. There are too many unknowns and hit a brick wall.
Appreciate any help |
| 4 L A T E S T R E P L I E S (Newest First) |
| Subhotosh Khan |
Posted - 04/01/2008 : 22:36:30
quote:
Originally posted by raghu
Here is how I solved the problem. Face diagonal will be of size sqrt(2) and space diagonal will be sqrt(3).
The angle between the two diagonals will be sine inverse of (1/sqrt3)
correct
. So the angle is 60 degrees.incorrect
sin-1(1/ 3) = 35.26438968
Mr. Khan,
thanks for the response.
|
| raghu |
Posted - 04/01/2008 : 18:20:30
Here is how I solved the problem. Face diagonal will be of size sqrt(2) and space diagonal will be sqrt(3).
The angle between the two diagonals will be sine inverse of (1/sqrt3). So the angle is 60 degrees.
Mr. Khan,
thanks for the response. |
| raghu |
Posted - 04/01/2008 : 14:45:11
can you please expand on that. |
| Subhotosh Khan |
Posted - 04/01/2008 : 14:15:22
Express the diagonals as vectors - then use definition of vector product to find the angle. |
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