Trig and Invert question

Basically what I am trying to do is calculate the angle between an origin point and the mouse position.

I have a function which declares an origin and establishes the opposite and adjacent (and therefore you can calculate the hypotenuse) of the triangle.

I then divide the opposite by the hypotenuse to give me the sine of the angle I ma trying to get. I then want to invert this to give me the actual angle, but there is no invert function in BMax?

Does anyone have any suggestions or easier ways to achieve this?
cheers

Yeah, there is. It's called ASin (arcus sinus).

ATan((y1-y0)/(x1-x0)), or ATan2((y1-y0),(x1-x0)).

working example of flame ducks suggestion:

Graphics 800, 600, 0, 60

SeedRnd(MilliSecs())

Global oy = Rand(0, GraphicsHeight())
Global ox = Rand(0, GraphicsWidth())

While Not KeyHit(KEY_ESCAPE)
	Cls
	
	DrawOval ox - 5, oy - 5, 10, 10
	
	angle = ATan2(ox - MouseX(), oy - MouseY()) + 180
	DrawLine ox, oy, MouseX(), MouseY()
	DrawText angle, 10, 10
	
	Flip
Wend

Thanks fellas, fantastic