Actually Welcome to the Concept of the Trigonometry.
The value of Sin30° is 1/2,
Proof:-
=> Let us now calculate the sin 30 value. Consider an equilateral triangle ABC. Since each angle in an equilateral triangle is 60°, therefore ∠A=∠B=∠C=60∘.
Draw the perpendicular line AD from A to the side BC (From figure)
Now ΔABD≅ΔACD
Therefore BD=DC and also
∠BAD=∠CAD
Now observe that the triangle ABD is a right triangle, right-angled at D with ∠BAD=30∘ and ∠ABD=60∘.
As you know, for finding the trigonometric ratios, we need to know the lengths of the sides of the triangle. So, let us suppose that AB=2a
BD=12BC=a
To find the sin 30-degree value, let’s use sin 30-degree formula and it is written as:
Sin 30° = opposite side/hypotenuse side
We know that, Sin 30° = BD/AB = a/2a = 1 / 2
Therefore, Sin 30 degree equals to the fractional value of 1/ 2.
Sin 30° = 1 / 2
==> Therefore, sin 30 value is 1/2.