Does anyone know what math topic this is?

If you're talking about things like Algebra and Geometry, its Geometry

If you're not, can you be more specific ? :D

Geometry (trigonometry)

Step-by-step explanation:

Trigonometry is the branch of mathematics concerned with specific functions of angles and their application to calculations. There are six functions of an angle commonly used in trigonometry which I believe is the problem you are on.

Hope this helps <3

for this case we have by definition, if two lines are perpendicular, then the product of their slopes is -1.

then, given the following line:

so,

we are looking for m_ {2}:

then, the line is given by:

we find "b" replacing the given point:

finally, the equation is:

option c