10th Class Mathematics Introduction to Trigonometry Question Bank Case Based (MCQs) - Introduction to Trigonometry

In above triangle, what is the length of BC?

A) \[5\,ft\]

B) \[6\,ft\]

C) \[8\,ft\]

D) \[4\sqrt{3}\,ft\]

Correct Answer: B

Solution :

In right \[\Delta ABC,\]

\[\tan 30{}^\circ =\frac{AB}{BC}\,\,\,\,\,\,\,\Rightarrow \,\,\,\,\,\frac{1}{\sqrt{3}}=\frac{4}{BC}\,\,\,\,\,\Rightarrow \,\,\,BC=4\sqrt{3}ft\]

So, option [d] is correct.