Deductive reasoning - Logic

Deductive reasoning

Lessons

Notes:

Deductive Reasoning uses definitions, rules, and properties to see if a statement is true or false. There are two forms of deductive reasoning: Law of Detachment, and Law of Syllogism.

Law of Detachment states the following:

If pqp\to q is true and pp is true, then qq must also be true

Law of Syllogism states the following:

If pqp \to q and qrq \to r are true, then prp \to r must be also true.

  • Intro Lesson
    Deductive Reasoning Overview:
  • 1.
    Using the Law of Detachment
    You are given the statements below. Assume these statements are true. Determine if a conclusion can be made by using the Law of Detachment.
  • 2.
    Given the information and a statement below, determine if the conclusion is valid. Explain why it is valid or invalid.
    If two lines are perpendicular, then they intersect
  • 3.
    Using the Law of Syllogism
    You are given the statements below. Assume these statements are true. Determine if a conclusion can be made by using the Law of Syllogism.
  • 4.
    Given the information below, determine if the conclusion is valid. Explain why it is valid or invalid.
Teacher pug

Deductive reasoning

Don't just watch, practice makes perfect.

We have over 160 practice questions in Geometry for you to master.