Question

what is the value of sin 30_??

Answer 1

Answer:

0.5

Step-by-step explanation:

sin(30)

=0.5

Answer 2

$\huge\sf\pink{Answer}$

☞ sin 30° = ½

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$\huge\sf\blue{Given}$

✭ ∆OBC is an equilateral triangle

✭ Let the radius of the circle be 1

✭ BD is a perpendicular

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$\huge\sf\gray{To \:Find}$

◈ Value of sin 30°?

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$\huge\sf\purple{Steps}$

So we know that in an equilateral triangle all the angles are 60° and so then ∠BOC will be 30°

In ∆OBC

• OC = a
• OD = a/2
• OB = 1

So now in ∆OBD & ∆BDC

➝ O$\sf D = DC$

➝ $\sf \angle BDO = \angle BDC$

➝ $\sf BD = BD$

$\sf \therefore \triangle OBD \cong \triangle BDC$ «« SAS »»

Now we know that all congruent triangles are similar,so,then

➳ $\sf \dfrac{BD}{BO} = \dfrac{OD}{BO}$

➳ $\sf sin \ 30^{\circ} = \dfrac{\dfrac{a}{2}}{a}$

➳ $\sf sin \ 30^{\circ} = \dfrac{a}{2} \times \dfrac{1}{a}$

➳ $\sf \orange{sin \ 30^{\circ} = \dfrac{1}{2}}$

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