Answer:Let's address each of your questions quickly: 6. Outside the Polygon between a Side and an Extension: - The angle formed outside the polygon between a side and an extension of an adjacent side is called an exterior angle.7. Interior Angle Adjacent to 21: - The interior angle adjacent to angle 21 is angle 20.8. Relation between 21 and 22: - Angles 21 and 22 are supplementary angles because they add up to 180°.9. Sum of Measures of 21 and 10, and Measure of 21: - The sum of the measures of angles 21 and 10 is 180° because they form a straight line.- If the measure of angle 22 is 120°, then the measure of angle 21 can be found using the fact that angles 21 and 22 are supplementary.- Measure of angle 21 = 180° - Measure of angle 22- Measure of angle 21 = 180° - 120° = 60°10. Finding Interior Angle from Exterior Angle: - In a regular polygon, the sum of an exterior angle and its corresponding interior angle is always 180°.- To find the measure of the interior angle of a regular polygon when the exterior angle is given, subtract the exterior angle from 180°. I hope this helps you quickly with your geometry questions! Let me know if you need further assistance or have more questions.