School Improvement in Maryland

Lesson Plan: Lesson plans were written by Maryland mathematics educators and could be used when teaching the concepts.

Goal 2 Geometry, Measurement, And Reasoning

Expectation 2.2 The student will apply geometric properties and relationships to solve problems using tools and technology when appropriate.

Indicator 2.2.3 The student will use inductive or deductive reasoning.

Lesson Content

Paragraph Proofs

Objective

Students will be able to identify and apply properties of equality and properties of congruence, write paragraph proofs for organizing deductive arguments, and validate properties of geometric figures and explain the processes used.

Approximate Time

50-minute lesson

Prerequisite Concepts Needed

The student will need to be able to interpret and analyze conditional statements.

Materials Needed

Lesson Structure

    Essential Questions

    How can deductive reasoning be used to validate conjectures?
     
    What methods can be used to organize a deductive argument?

    Warm-Up/Opening Activity

    Construct a flow chart demonstrating the steps taken to get ready for school.

    Development of Ideas

    Convert the boxes of the flowchart to sentences and form a paragraph showing the steps taken to get ready for school.
     
    Convert flow-chart proofs to paragraph proofs.
     
    Justify geometric properties in paragraph form.
     
    Worksheet: Introduction to Paragraph Proofs
     
    Justify geometric properties in paragraph form.
     
    Worksheet: Paragraph Proofs

    Closure

    Explain how deductive reasoning is used in paragraph proofs.
     
    Answer: Deductive reasoning is used to connect the given statements by use of definitions, theorems, and postulates to what is to be proved.

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