When the hour hand moves from 3 pm to 6 pm, through how many degrees does it move? A. 3⁰
B. 90⁰
C. 18⁰
D. 36⁰

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