19.
Which conclusion is not justified by the prior given statements?
A. Given: If a line is vertical, then it has an undefined slope.
Given: Line / is vertical.
Conclusion: Line / has an undefined slope.
B. Given: If a triangle is isosceles, then it has two congruent sides.
Given: If a triangle has two congruent sides, then it has two congruent angles.
Conclusion: If a triangle is isosceles, then it has two congruent angles.
C. Given: If two angles are vertical, then they are congruent angles.
Given: 21 and 22 are vertical angles.
Conclusion: 21 22
D. Given: If Mark goes fishing, then he will buy a new fishing rod.
Given: If Mark goes fishing, then he will need to buy bait.
Conclusion: If Mark buys a new fishing rod, then he will need to buy bait.