How do we solve logic problems using conditionals?

Ex:
Two angles are congruent( hypothesis)
Two angles are both right angles(conclusion)
 Then you just combine them and create one sentence by creating the inverse....
"if two angles are not congruent, then the two angles are not right triangles"

When the conditional and  converse are both true is it called a bi-conditional
Ex: " Next month is September if and only if this moth is August"
Contrapositive:
Contra - prefix meaning "against" or "opposite"
 So just negate and switch the hypothesis and conclusion ( inverse and converse)
Ex: " If i study, then i'll pass geometry"
Ans: "If  i did not pass geometry,then i did not study"