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Question:

In ΔABC, AB=6√3cm, AC=12cm and BC=6cm. The ∠B is :

120o

90o

60o

45o

Solution:

The correct option is C
90o
Given:In ΔABC
AB=6√3cm
AC=12cm
BC=6cm
Solution:
AC²=144
AB²=108
BC²=36
Since, AC²=AB²+BC²
∴By Converse of Pythagoras Theorem, ΔABC is an Right Angle Triangle at B.
∴∠B=90o