Answer:
11. Definition of a Right Angle (F)
12. Definition of Supplementary Angles (D)
13. Definition of Congruence (A)
14. Definition of Complimentary Angles (C)
15. Congruent Supplements Theorem (L)
16. Vertical Angles Theorem (H)
17. Congruent Compliments Theorem (K)
18. Linear Pair (Supplementary) Theorem (J)
Explanation:
General Definitions:
Definition of Congruence - identical in shape and size (applies to line segments and angles)
Definition of Angle Bisector - a line that splits one angle into two equal angles
Definition of Complementary Angles - two angles that sum to 90 degrees
Definition of Supplementary Angles - two angles that sum to 180 degrees
Definition of Perpendicular - two lines that meet or intersect each other at 90 degrees
Definition of a Right Angle - an angle whose measure is 90
Angle Addition Postulate - the sum of two adjacent angles will equal the measure of the angle they make together
Vertical Angles Theorem - the vertical angles that form when two lines intersect are congruent (aka identical in shape and size)
Complement Theorem - if two angles are complements of the same angle, then those two angles are congruent (also applies if the two angles are congruent)
Linear Pair (Supplement) Theorem - if two angles form a linear pair, then they are supplementary
Congruent Complements Theorem - if two angles are complements of the same angle, then the two angles are congruent (also applies if the two angles are congruent angles)
Congruent Supplements Theorem - if two angles are supplements of the same angle, then the two angles are congruent (also applies if the two angles are congruent)
Solving 11-18:
11. Definition of a Right Angle (F)
12. Definition of Supplementary Angles (D)
13. Definition of Congruence (A)
14. Definition of Complimentary Angles (C)
15. Congruent Supplements Theorem (L)
16. Vertical Angles Theorem (H)
17. Congruent Compliments Theorem (K)
18. Linear Pair (Supplementary) Theorem (J)
Note that these were answered assuming only one letter corresponded to each statement, and also each letter could be only used once.