What you’ll learn
Understand exterior-angle relationships.
Key idea
An exterior angle equals the remote-interior sum and is supplementary to its adjacent interior angle.
Exterior equals remote sum and supplements adjacent interior; keep the three roles distinct.
Worked example
Classify examples and non-examples for the concept 'Understand exterior-angle relationships'.
Remote interior angles are 25,35 degrees. Classify proposed exterior angle 70 degrees with relationship evidence.
- Remote interior angles 25 and 35 sum to exterior 60 degrees.
- Adjacent interior 120 and exterior 60 form a straight angle; missing remote angle=60-25=35.
Answer: False — remote sum 25+35=60 degrees is the exterior measure.
Quick Check
Classify examples and non-examples for the concept 'Understand exterior-angle relationships'.
Remote interior angles are 35,30 degrees. Classify proposed exterior angle 65 degrees with relationship evidence.