Understanding Reflex Angles

What is the first step in measuring the reflex angle ABC?

• Place the protractor on angle ABC

• Extend arm CB to D

• Measure angle DBA directly

• Use the inner scale of the protractor

How should the protractor be positioned to measure angle DBA?

• With the outer scale starting at 90°

• Upside down with the center over point B

• With the baseline along arm BA

• With the center over point A

Which scale on the protractor is used to measure angle DBA?

• Inner scale

• Outer scale

• Neither scale

• Both scales

What is the measure of angle DBA?

• 90°

• 60°

• 30°

• 45°

How is the reflex angle ABC calculated?

• By using only angle CBD

• By subtracting angle DBA from 180°

• By adding angles CBD and DBA

• By measuring directly with a protractor