Can you say what angle is made by the two red lines drawn on two sides of the cube as shown in the illustration?
(In reply to
answer by K Sengupta)
Let us number the faces as follows:
The bottom face (unseen) is numbered 4
Let each of the sides have length s (say)
+ _________
| \ 2 \
| +-----------+
| 3 | 1 |
| | |
\ +-----------+
Let us join the two points at the bottom to describe the base BC
Then we have a triangle ABC, where:
AC= length of the diagonal in face 1 = s*V2
AB = length of the diagonal in face 3 = s*V2
BC = length of the diagonal in face 4 = s*V2
Therefore AC =AB=BC
Accordingly, the triangle ABC is equilateral, each of whose angles must equal 60 degrees.
Consequently, our desired angle BAC is equal to 60 degrees.
*** I may please be excused for my bad ASCII drawing, since I still have not been able to perfect that art.
Edited on July 17, 2022, 11:22 pm
explanation to puzzle answer
