The contrapositive of a conditional statement is a combination of the converse and the inverse. The “If” part or p is replaced with the “then” part or q and the “then” part or q is replaced with the “If” part or p. After that, both parts are negated.

• In Geometry the conditional statement is referred to as p → q.
• The Contrapositive is referred to as ~q → ~p.

Examples: 

Conditional statement:	If three points lie on a line,	then the three points are collinear
	Hypothesis / p	Conclusion / q

Contrapositive statement:	If three points are NOT collinear,	then the three points DO NOT lie on a line.
	New Hypothesis / q	The negation of the NewConclusion / p

Fill in the blanks.

Conditional statement: If it is an acute triangle, then all three interior angles have a measure less than 90°.

• The hypothesis or p is: Interactive button. Assistance may be required. _______________. it is an acute triangle
  
  
• The negation of the hypothesis or p is: Interactive button. Assistance may be required. _______________. it is not an acute triangle
  
  
• The conclusion or q is: Interactive button. Assistance may be required. _______________. all three interior angles have a measure less than 90°
  
  
• The negation of the conclusion or q is: Interactive button. Assistance may be required. _______________. all three angles do NOT have a measure less than 90°
  
  
• The Contrapositive statement is: Interactive button. Assistance may be required. _______________. If all three angles do not have a measure less than 90°, then it is not an acute triangle.
  
  
• A geometrical representation of the contrapositive statement is Interactive button. Assistance may be required. _______________. ~q → ~p