How find sin30?

Answer 1

On a calculator type in 'Sin' , followed by '30' follwed by '=' . The answer is '0,5'.

Sin(30) = 0.5

All the trig. values are based on a triangle integrated into a circle.

Practically,

On a piece of graph paper, draw a circle centred on the origin (0,0).

Call the radius of that circle '1'.

Now draw a radius 30 degrees from the x-axis.

Then drop a line from point on the circle were the radius meets( intersects) the circle. to the x-axis, to meet the x-axis at 90 degrees. This 'dropped' line is the 'opposite' to the angle 30 degrees. Measure the length of this 'dropped'; line. You will find it to be exactly half (0.5 = 1/2) the length of the radius.

Similarly, if the radial angle is 45 degrees a corresponding sine value is 0.707106781... = sqrt(2)/2 = 1/sqrt(2).

All other 'Sine' values can be found in a similar manner. However, to save time on drawing circles and triangles, the trig. values are integrated into modern calculators or formerly into Castle's Four Figure Tables.

Answer 2

when we taking the right angle triangle,in this when taking the 30 degrees of one side ,then the ratio of the opposite side to the hypotenuse will 0.5 always.and this is called sin30 in trigonometry and...............this is answered by sreenivassn from narayana engineering college,gudur.