gaokao 2017 Q10

gaokao · China · national-II-science Vectors 3D & Lines MCQ: Angle Between Skew Lines
10. In a right triangular prism $A B C - A _ { 1 } B _ { 1 } C _ { 1 }$, $\angle A B C = 120 ^ { \circ } , A B = 2 , B C = C C _ { 1 } = 1$. The cosine of the angle between skew lines $A B _ { 1 }$ and $B C _ { 1 }$ is
A. $\frac { \sqrt { 3 } } { 2 }$
B. $\frac { \sqrt { 15 } } { 5 }$
C. $\frac { \sqrt { 10 } } { 5 }$
D. $\frac { \sqrt { 3 } } { 3 }$ [Figure] 
10. In a right triangular prism $A B C - A _ { 1 } B _ { 1 } C _ { 1 }$, $\angle A B C = 120 ^ { \circ } , A B = 2 , B C = C C _ { 1 } = 1$. The cosine of the angle between skew lines $A B _ { 1 }$ and $B C _ { 1 }$ is\\
A. $\frac { \sqrt { 3 } } { 2 }$\\
B. $\frac { \sqrt { 15 } } { 5 }$\\
C. $\frac { \sqrt { 10 } } { 5 }$\\
D. $\frac { \sqrt { 3 } } { 3 }$\\
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Paper Questions
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