Proving Lines Parallel: Key Concepts and Techniques

This video tutorial focuses on proving that lines are parallel using logical statements and the converse of postulates and theorems. It covers four methods: corresponding angles, alternate interior angles, alternate exterior angles, and same side interior angles. The tutorial includes step-by-step examples and emphasizes the importance of marking diagrams to visualize angle relationships. It also provides strategies for identifying parallel lines and transversals in complex diagrams.

What are the learning goals for proving lines parallel?

• Understanding the properties of circles

• Understanding the properties of triangles

• Knowing the logical statements and methods to prove lines parallel

• Learning about different types of quadrilaterals

Tags

CCSS.4.G.A.1

CCSS.HSG.CO.A.1

Which logical statement is used to prove lines are parallel?

• The original postulate or theorem

• The converse of the postulate or theorem

• The inverse of the postulate or theorem

• The contrapositive of the postulate or theorem

Tags

CCSS.8.G.A.5

What must be true about corresponding angles to prove lines are parallel?

• They must be supplementary

• They must be complementary

• They must be congruent

• They must be adjacent

Tags

CCSS.8.G.A.5

What must be true about alternate interior angles to prove lines are parallel?

• They must be adjacent

• They must be congruent

• They must be complementary

• They must be supplementary

Tags

CCSS.8.G.A.5

What must be true about alternate exterior angles to prove lines are parallel?

• They must be complementary

• They must be supplementary

• They must be congruent

• They must be adjacent

Tags

CCSS.8.G.A.5

What must be true about same side interior angles to prove lines are parallel?

• They must be adjacent

• They must be congruent

• They must be supplementary

• They must be complementary

Tags

CCSS.8.G.A.5

In the first example proof, what is the reason for marking G as parallel to H?

• It is assumed

• It is given

• It is proven

• It is calculated

Tags

CCSS.8.G.A.5

In the first example proof, which angles are congruent due to the corresponding angles postulate?

• 1 and 11

• 7 and 11

• 1 and 7

• 4 and 9

Tags

CCSS.8.G.A.5

In the second example proof, which theorem is used to prove that four and five are supplementary?

• Alternate Exterior Angles Theorem

• Alternate Interior Angles Theorem

• Corresponding Angles Postulate

• Same Side Interior Angles Theorem

Tags

CCSS.8.G.A.5

What is the final step to prove that G is parallel to H in the second example proof?

• Using the original postulate

• Using the converse of the corresponding angles postulate

• Using the congruent supplements theorem

• Using the transitive property

Tags

CCSS.8.G.A.5