Honors Geometry Companion Book, Volume 1

2.2.3 Flowchart and Paragraph Proofs − Practice

1.  Write a flowchart proof for the two-column proof. Given: m ∠ a = 24° and m ∠ b = 24° Prove: ∠ a ≅ ∠ b Two-Column Proof 1.m ∠ a = 24° (Given) 2.m ∠ b = 24° (Given) 3.m ∠ a = m ∠ b (Trans. Prop. of = ) 4. ∠ a ≅ ∠ b (Def. of ≅ ∠ s )

2.  Write a flowchart proof for the two-column proof. Given: m ∠ PQR = 90° and m ∠ b = 5 ∙ m ∠ a

Prove: m ∠ a = 15° Two-Column Proof 1.m ∠ PQR = 90°,

m ∠ a = 5 ∙ m ∠ a (Given) 2.m ∠ a + m ∠ b = m ∠ PQR ( ∠ s Add. Post.) 3.m ∠ a + 5 ∙ m ∠ a = 90° (Subst. Prop. of = ) 4. 6 ∙ m ∠ a = 90° (Simplify.) 5.m ∠ a = 15° (Div. Prop. of = )

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