sin 30

In a triangle, When one angle is 30 degrees(given). Then the other two angles are 90 and 60 degrees. Express in the form of ratio: 30:60:90, the sides are in the ratio of 1: \sqrt{3} :2. The sine function is defined as the ratio of opposite side to the hypotenuse. For 30 degrees, the ratio is 1/2. Therefore, \sin30^0=\frac{1}{2}