8/31 DO NOW

Which of the following statements is ALWAYS TRUE when parallel lines are cut by a transversal?

• The sum of the degree measure of corresponding angles is 180°.
• The sum of the degree measure of complementary angles is 180°.
• The angles in a vertical pair are acute.
• Corresponding angles are supplementary.
• Corresponding angles are congruent.

Answer explanation

Double check your glossary! Look at vertical angles, supplementary angles, complementary angles, and corresponding angles to see which statement is true. hint we're looking at parallel lines

In the figure below of a parallel lines cut by a transversal, which angle is supplementary to ∠8?

• ∠1
• ∠3
• ∠4
• ∠5
• none of the above

Answer explanation

1 and 8: alternate exterior (congruent)

4 and 8: corresponding (congruent)

5 and 8: vertical (congruent)

3 and 4: linear pair (supplementary) SO

3 and 8: supplementary because 4=8

Use the following figure to determine which statements are true.

• ∠ABD and ∠DBC are a linear pair.
• ∠ABE and ∠EBC are adjacent.
• ∠DBE and ∠EBC are adjacent.
• ∠EBC and ∠EBA are a linear pair.
• All of the above are true.

Answer explanation

Don't choose a final answer until you have checked EVERY answer choice!

In the diagram of parallel lines cut by a transversal, shown below, which of the following statements is false?

• ∠3 and ∠4 are vertical angles.
• ∠5 and ∠8 are corresponding angles.
• ∠3 and ∠5 are alternate interior angles.
• ∠2 and ∠8 are alternate exterior angles.
• All of the above are false.

Answer explanation

3 and 4: LINEar pair

5 and 8: VERTICAL angles

3 and 5: SAME SIDE interior

2 and 8: SAME SIDE exterior

The following diagram shows parallel lines cut by a transversal. What is the measure of ∠2?

• 80°
• 100°
• 20°
• 160°
• 50°

Answer explanation

Solve for x first using the two angle relationships (5x+55 and 2x+100)

THEN find either 5x+55 or 2x+100 and calculate angle 2 using another angle relationship

Which of the statements below is ALWAYS TRUE?

• Supplementary angles are both obtuse angles.
• Complementary angles are both acute angles.
• At least one of the angles in a supplementary pair is obtuse.
• Alternate exterior angles are both obtuse angles.
• Any two acute angles are complementary.

The following diagram shows parallel lines cut by a transversal. What is the value of x?

• 9°
• 75°
• 115°
• 3°
• 5°

Answer explanation

What is the relationship between the 75 degree angle and the 15x-30 angle? Are they congruent? Supplementary?

Two angles are a linear pair. Their measures are represented by x+10, and 3x+10. What are the measures of the angles?

• 40° and 40°
• 40° and 140°
• 50° and 130°
• 60° and 120°
• 90° and 90°

Answer explanation

What does a linear pair mean for the angle measurements? Are they equal/congruent? Complementary? Supplementary?