1. Given: ABL BC;
 21 and 23 are
 complementary.
 Prove: 42 = 23
 Proof:
 Statements
 a. AB 1 BC
 b.
 c. m/ABC = 90
 d. m/ABC:
 m21+ m22
 e. 90 m/1 +
 =
 m22
 f. 21 and 22 are
 compl.
 g.
 h. 22 23
 B
 Reasons
 W/N
 E
 f.
 D
 a.
 Given
 b. Definition of 1
 C
 c. Def. of right angle
 d.
 color
 e. Substitution
 g. Given
 1. Subst prop