Easy Tutorial
For Competitive Exams

CBSE 10th Maths Chapter 8 - Introduction to Trigonometry-Multiple choice questions (MCQs)

58534.In $\triangle$ ABC, right-angled at B, AB = 24 cm, BC = 7 cm. The value of tan C is:
$\dfrac{12}{7}$
$\dfrac{24}{7}$
$\dfrac{20}{7}$
$\dfrac{7}{24}$
Explanation:

AB = 24 cm and BC = 7 cm

tan C = Opposite side/Adjacent side

tan C = $\dfrac{24}{7}$

58535.(Sin 30°+cos 60°)-(sin 60° + cos 30°) is equal to:
0
1+2$\sqrt{3}$
1-$\sqrt{3}$
1+$\sqrt{3}$
Explanation:

sin 30° = $\dfrac{1}{2}$ sin 60° =$\dfrac{\sqrt{3}}{2}$, cos 30° = $\dfrac{\sqrt{3}}{2}$ and cos 60°= $\dfrac{1}{2}$

Putting these values, we get:

$(\dfrac{1}{2}+\dfrac{1}{2})-(\dfrac{\sqrt{3}}{2}+\dfrac{\sqrt{3}}{2})$

=$ 1 – [\dfrac{(2\sqrt{3})}{2}]$

= 1 – $\sqrt{3}$

58536.The value of $\dfrac{tan 60°}{cot 30°}$ is equal to:
0
1
2
3
Explanation:

tan 60° =$ \sqrt{3}$ and cot 30° = $\sqrt{3}$

Hence, $\dfrac{tan 60°}{cot 30°}$ =$\dfrac{ \sqrt{3}}{\sqrt{3}}$= 1

58537.1 – $cos^{2}$A is equal to:
$sin^{2}A$
$tan^{2}A$
$1 – sin^{2}A$
$sec^{2}A$
Explanation:

We know, by trigonometry identities,

$sin^{2}A$ + $cos^{2}A$ = 1

1 –$cos^{2}A$ =$sin^{2}A$

58538.sin (90° – A) and cos A are:
Different
Same
Not related
None of the above
Explanation:

By trigonometry identities.

Sin (90°-A) = cos A {since 90°-A comes in the first quadrant of unit circle}

58539.If cos X = $\dfrac{2}{3}$ then tan X is equal to:
$\dfrac{5}{2}$
$ \sqrt{\dfrac{2}{3}}$
$\dfrac{\sqrt{5}}{2}$
$\dfrac{2}{\sqrt{5}}$
Explanation:

By trigonometry identities, we know:

$1 + tan^{2}X $= $sec^{2}X$

And sec X = $\dfrac{1}{cos X}$ =$ \dfrac{1}{(\dfrac{2}{3})}$ =$ \dfrac{3}{2}$

Hence,

$1 + tan^{2}X$ = $(\dfrac{3}{2})^{2}$ =$ \dfrac{9}{4}$

$tan^{2}X$ = $(\dfrac{9}{4}) $– 1 = $\dfrac{5}{4}$

tan X = $\dfrac{\sqrt{5}}{2}$

58540.If cos X = $\dfrac{a}{b}$, then sin X is equal to:
$\dfrac{(b^{2}-a^{2})}{b}$
$\dfrac{(b-a)}{b}$
$\dfrac{\sqrt{(b^{2}-a^{2})}}{b}$
$\dfrac{\sqrt{(b-a)}}{b}$
Explanation:

cos X = $\dfrac{a}{b}$

By trigonometry identities, we know that:

$sin^{2}X + cos^{2}X$ = 1

$sin^{2}X$ = $1 – cos^{2}X$ = $1-(a/b)^{2}$

sin X = $\dfrac{\sqrt{(b^{2}-a^{2})}}{b}$

58541.The value of sin 60° cos 30° + sin 30° cos 60° is:
0
1
2
4
Explanation:

sin 60° = $\dfrac{\sqrt{3}}{2}$, sin 30° =$\dfrac{1}{2}$, cos 60° =$\dfrac{1}{2}$ and cos 30° = $\dfrac{\sqrt{3}}{2}$

Therefore,

($\dfrac{\sqrt{3}}{2}$) x ($\dfrac{\sqrt{3}}{2}$) + ($\dfrac{1}{2}$) x ($\dfrac{1}{2}$)

= ($\dfrac{3}{4}$) + ($\dfrac{1}{4}$)

= $\dfrac{4}{4}$

= 1

58542.$\dfrac{2 tan 30°}{(1 + tan^{2}30°)}$ =
sin 60°
cos 60°
tan 60°
sin 30°
Explanation:

tan 30° = $\dfrac{1}{\sqrt{3}}$

Putting this value we get;

$\dfrac{[2(\dfrac{1}{\sqrt{3}})]}{[1 + (\dfrac{1}{\sqrt{3}})^{2}] }$

=$\dfrac{(\dfrac{2}{\sqrt{3}})}{( \dfrac{4}{3}) }$

= $\dfrac{6}{4\sqrt{3} }$

=$\dfrac{\sqrt{3}}{2 }$

= sin 60°

58543.sin 2A = 2 sin A is true when A =
30°
45°
60°
Explanation:

sin 2A = sin 0° = 0

2 sin A = 2 sin 0° = 0

Share with Friends