Deductive Reasoning - Laws & Errors

• Law of Detachment

• Law of Syllogism

• Law of the Contrapositive

• Law of Logic

• Law of Detachment

• Law of Syllogism

• Law of the Contrapositive

• Law of Logic

• Law of Detachment

• Law of Syllogism

• Law of the Contrapositive

• Law of Logic

• Inverse Error

• Converse Error

• Conditional Error

• Contrapositive Error

• Inverse Error

• Converse Error

• Conditional Error

• Contrapositive Error

Use deductive reasoning to determine the conclusion:

If I go to my Grandma's house, then I will eat cookies.

I ate cookies.

• I went to my Grandma's house - Law of Detachment

• I will eat cookies - Law of Syllogism

• No valid conclusion - Inverse Error

• No valid conclusion - Converse Error

Tags

CCSS.L.11-12.6

CCSS.L.8.6

CCSS.L.9-10.6

CCSS.W.11-12.2D

CCSS.W.9-10.2D

Use deductive reasoning to determine the conclusion:

If each angle in a triangle is less than 90, then the triangle is acute.

The three angles in triangle ABC are 40, 60, and 80.

• Triangle ABC is acute - Law of Detachment

• Triangle ABC is acute - Law of Syllogism

• No valid conclusion - Inverse Error

• No valid conclusion - Converse Error

Tags

CCSS.8.G.A.5

Use deductive reasoning to determine the conclusion:

If a polygon has 4 sides, then it is a quadrilateral

If a polygon is a quadrilateral, then it has 4 angles

• If a polygon has 4 sides, then it has 4 angles - Law of Syllogism

• If a polygon is a quadrilateral, then it has 4 angles - Law of Detachment

• No valid conclusion - Inverse Error

• No valid conclusion - Converse Error

Use deductive reasoning to determine the conclusion:

If you live in Greenville, then you live in South Carolina

Adrian does not live in South Carolina

• Adrian lives in Greenville - Law of Detachment

• Adrian does not live in Greenville - Law of the Contrapositive

• No valid conclusion - Inverse Error

• No valid conclusion - Converse Error

Use deductive reasoning to determine the conclusion:

If you go on vacation, then you go to the beach

You do not go on vacation

• You do not go to the beach - Law of Detachment

• You go to the beach - Law of Syllogism

• No valid conclusion - Inverse Error

• No valid conclusion - Converse Error