1103212903

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Project ID: 
1103212903
Source Problem: 
Accepted: 
1
Clonable: 
1
Easy: 
0
A cube ABCDEFGH with an edge length of 2 units is placed in a coordinate system (see the picture). Find an angle φ between the plane α passing through the points E, D and C and the straight line AF. Hint: An angle between a line and a plane is an angle between the line and its orthogonal projection into this plane.
φ=30
φ=15
φ=45
φ=60