# A Different Look at Angles

## Instructions

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## Questions

1. What is the measure of angle <AOC when A=(15,20)?

2. What is the slope of line AO?

3. Where do you need to put B so that the measure of angle <BOD is the same as #1?

4. What are the co-ordinates of point O (test your answer by moving point A there)?

5. Where can you place A so that <AOC is a 45° angle?

6. What is the slope of line AO now?

7. Where above the line OD can you place B so that <BOD is also a 45° angle?

8. What is the slope of OB?

9. Notice that AO and OB are perpendicular now. Place A at (40,20). Where can you place B so that AO and OB are perpendicular?

10. What is the slope of AO?

11. What is the slope of OB?

12. There is a relationship between the slopes of perpendicular lines. What is it?

13. If you are confident you know what the relationship is, predict where A should be so that AO and OB are perpendicular when B is at (10,-10). Where should A be?

14. What is the length of OB (use the Pythagorean theorem or the disance formula)

15. Where should B be placed so that OB is 13 in length and <BOD=112.6°?