A) 2
B) 3
C) 4
D) 5
Correct Answer: A
Solution :
Let the fourth side be of ?d? length. We know that \[A{{B}^{2}}+B{{C}^{2}}-2AB.BC\cos {{60}^{o}}=A{{C}^{2}}\] \[=C{{D}^{2}}+D{{A}^{2}}-2CD.DA\,\,\cos {{120}^{o}}\] (by cosine rule)You need to login to perform this action.
You will be redirected in
3 sec