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

Justification in Proof

### Objective

Students will be able to identify and apply properties of equality and properties of congruence, and validate properties of geometric figures and explain the processes used.

50-minute lesson

### Prerequisite Concepts Needed

Students will need to be able to interpret and analyze conditional statements.

### 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

Solve a two-step equation.

### Development of Ideas

Justify the steps to solve an equation using the properties of equality.

Identify and apply the properties of equality and the properties of congruence to geometric figures.

Worksheet: Justification Using Properties of Equality and Congruence

### Closure

Compare and contrast inductive and deductive reasoning.

Worksheet: Comparison of Inductive and Deductive Reasoning

/share/clg/xml/lesson_plans/mathematics/Proof_223.xml