PHP trigonometry TAN

Question

I try to figure out an angle of a triangle.

If one side of the triangle is 100 and the other side is 100.

How do I get that to be 45 degrees.

If I run tan^-1(100/100) on my calculator i get 45. How do I do this in PHP?

Answer 1

Use the atan function.

tan-1(100/100) on the calculator is the equivalent to atan(100/100) in Php.

Edit: Sorry, here's the same output as the calculator:

$input = 100 / 100;
print atan($input) * (180 / pi());
//Ouputs 45

Answer 2

Since you have both rise and run what you really want to use is atan2(), which will handle the difference between e.g. 1/4*pi and -3/4*pi properly.