In $\triangle ABC$,right-angled at $B$,$AB = 5 \, cm$ and $\angle ACB = 30^{\circ}$. Determine the lengths of the sides $BC$ and $AC$.

Vedclass pdf generator app on play store
Vedclass iOS app on app store
(N/A) To find the length of the side $BC$,we will choose the trigonometric ratio involving $BC$ and the given side $AB$. Since $BC$ is the side adjacent to angle $C$ and $AB$ is the side opposite to angle $C$,therefore:
$\frac{AB}{BC} = \tan C$
$\frac{5}{BC} = \tan 30^{\circ} = \frac{1}{\sqrt{3}}$
Which gives $BC = 5\sqrt{3} \, cm$.
To find the length of the side $AC$,we consider:
$\sin 30^{\circ} = \frac{AB}{AC}$
$\frac{1}{2} = \frac{5}{AC}$
$AC = 10 \, cm$.
Alternatively,we could have used the Pythagoras theorem to determine the third side:
$AC = \sqrt{AB^2 + BC^2} = \sqrt{5^2 + (5\sqrt{3})^2} \, cm = \sqrt{25 + 75} \, cm = \sqrt{100} \, cm = 10 \, cm$.

Explore More

Similar Questions

$\frac{1+\tan ^{2} A}{1+\cot ^{2} A} = \dots$

Prove the following identity,where the angles involved are acute angles for which the expressions are defined:
$\frac{\sin \theta - 2 \sin^3 \theta}{2 \cos^3 \theta - \cos \theta} = \tan \theta$

Difficult
View Solution

Prove the following identity,where the angles involved are acute angles for which the expressions are defined:
$(\operatorname{cosec} A - \sin A)(\sec A - \cos A) = \frac{1}{\tan A + \cot A}$

$(\sec A + \tan A)(1 - \sin A) = \dots$

In a right triangle $ABC$,right-angled at $B$. If $\tan A = 1$,then verify that $2 \sin A \cos A = 1$.

Vedclass Products

For Students

Vedclass Test Series

Mock tests in real JEE/NEET style with performance analysis. 5-day free trial.

Start Free Trial
For Teachers

Exam Paper Generator

Generate Set A/B/C/D exam papers from 7.5L+ questions in 2 minutes. 3 chapters free.

Try Free
For Institutes

Online Exam Module

Live online exams with unlimited students, 360° analytics & white-label branding.

See Demo