Question

How can the statement be rewritten as a conditional statement in if-then form?

Lines on a coordinate plane are perpendicular if they have opposite reciprocal slopes.

If lines on a coordinate plane have opposite reciprocal slopes, then they are perpendicular.
If lines are on a coordinate plane, then they are perpendicular.
If lines are on a coordinate plane, then they have opposite reciprocal slopes.
If lines have opposite reciprocal slopes and are perpendicular, then they are on a coordinate plane.

Answer 1

"If lines on a coordinate plane have opposite reciprocal slopes, then they are perpendicular."

(Antecedent: lines on a coordinate plane have opposite reciprocal slopes. Consequent: they are perpendicular.)