these drawings depict the steps to get the perpendicular line using a compas (and maybe a ruler)
remember that a line goes through 2 points so we need 2 different points to construct our perpendicular line
the first one is wrong because it doesn't constraint it to be perpendicular
it only has 1 point,
2nd is wrong as well, has only 1 point, the center
3rd is right
4th is correct, hold a sec
how did that 2nd upper arc have same beginig pointn for compass?
3rd on is answer