Activity 3. Write the converse, inverse and contrapositive of each conditional statement. 1. If three points are collinear, then they are on a straight line. 2. If an angle measures 80°, then it is acute. 3. If ∆ABC is equilateral, then it is isosceles. 4. If two lines intersect each other, then they are perpendicular
5. If two angles are vertical, then they are congruent.