Which of the following is true of two lines that are perpendicular? their slopes are the same (for example: m1=2, m2=2) their slopes are the same and have different signs (for example: m1=2, m2=-2) their slopes are the inverse of each other and have different signs (for example: m1=2, m2=-1/2) their slopes are the inverse of each other and have the same signs (for example: m1=2, m2=1/2)