How do you get the angle from sin?

Question

I have a value for sin:

var opposite = 100;
var hypotenuse = 228;

var sin = opposite/hypotenuse;

I want to know what angle that is. On my calculator I can just do sin^-1(). This thread says to use asin but when I use asin I get 45°. The correct angle is 25°.

Answer 1

Because the arcus sinus returns result in radians and radian is defined as

you should convert result to degrees this way

var opposite = 100;
var hypotenuse = 228;

var sin = opposite/hypotenuse;

var angle = Math.asin(sin)*180/Math.PI;

document.body.innerHTML = angle;

example:

http://jsfiddle.net/o69xjayh/