In the adjoining figure, the value of cos θ is 1. 12/13 2. 13/12 3. 5/12 4. 5/13

In right angled triangle BDC, ⇒ BC 2 = BD 2 + CD 2 ⇒ BC 2 = (4) 2 + (3) 2 ⇒ BC 2 = 16 + 9 ⇒ BC 2 = 25 ⇒ BC = = 5 cm. In right angled triangle ABC, ⇒ AC 2 = AB 2 + BC 2 ⇒ AC 2 = (12) 2 + (5) 2 ⇒ AC 2 = 144 + 25 ⇒ AC 2 = 169 ⇒ AC = = 13 cm. By formula, cos θ = = . Hence, Option 1 is the correct option.

Mathematics

In the adjoining figure, the value of cos θ is
$\dfrac{12}{13}$
$\dfrac{13}{12}$
$\dfrac{5}{12}$
$\dfrac{5}{13}$

Trigonometrical Ratios

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Answer

In right angled triangle BDC,

⇒ BC² = BD² + CD²

⇒ BC² = (4)² + (3)²

⇒ BC² = 16 + 9

⇒ BC² = 25

⇒ BC = $\sqrt{25}$ = 5 cm.

In right angled triangle ABC,

⇒ AC² = AB² + BC²

⇒ AC² = (12)² + (5)²

⇒ AC² = 144 + 25

⇒ AC² = 169

⇒ AC = $\sqrt{169}$ = 13 cm.

By formula,

cos θ = $\dfrac{\text{Base}}{\text{Hypotenuse}}$

= $\dfrac{AB}{AC} = \dfrac{12}{13}$ .

Hence, Option 1 is the correct option.

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Mathematics

In the adjoining figure, the value of cos θ is
$\dfrac{12}{13}$
$\dfrac{13}{12}$
$\dfrac{5}{12}$
$\dfrac{5}{13}$

Trigonometrical Ratios

Answer

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