What is the exposition of the book all quiet on the western front ?

What is the missing statement in step 3 of the proof? given: z1 is complementary to 22. 22 is complementary to 23. prove: m_1 = m23 m21 = m2 m2 1 + m22 = 90° m22 = m23 m22 + m23 = 180° 2 statements 21 is comp. to 22 2. 22 is comp. to 23 3. ? 4. mz1 - 90°-m22 m22+m23 = 90° 6. m23 = 90°-m22 7 m21 - m23 reasons 1. given 2. given 3. def of comp. zs 4. subtr equality prop. 5. def. of comp. 25 6 subtr. equality prop 17. trans. prop. vo

In 300 words or less, summarize the prologue

The compass tests are tools used: a. when students are preparing for the act or sat. b. in lieu of the act or sat. c. when students score extremely high on the act or sat. d. to determine which level of classes a student should be placed in.