## OpenSessame 2 years ago CD is tangent to circle O at D. Find the diameter of the circle for BC = 13 and DC = 30. Round to the nearest tenth. (The diagram is not drawn to scale.)

1. OpenSessame
2. Directrix

The theorem you need to solve this problem is attached below.

3. OpenSessame

I see that but i really dont get how to do it.

4. OpenSessame

wait! 13(13=30)

5. OpenSessame

13(13+30)

6. Directrix

See if you can solve the equation. 30² = 13( 13 + x) where x = AB, the diameter of the circle.

7. OpenSessame

Ohh...Okay

8. OpenSessame

56.23

9. Directrix

On the equation you wrote, you forgot to square the tangent length.

10. OpenSessame

Oh i see

11. OpenSessame

Is 56 right?

12. Directrix

56.231 for x = AB which is the diameter is what I got. Same as your answer.

13. Directrix

Round to the nearest tenth.

14. OpenSessame

Okay thanks! Can you help me out with some other ones too please?

15. Directrix

What is 56.231 to the nearest tenth?

16. OpenSessame

56.2

17. Directrix

Yes.

18. Directrix

19. OpenSessame

Circle O and circle P are congruent. What can you conclude from the diagram? https://study.ashworthcollege.edu/access/content/group/45b8c516-1008-46d7-aa1d-bb9b62c786ff/geometry_exam_12_files/mc001-1.jpg

20. OpenSessame

21. Directrix

I think you need the theorem that begins: In the same circle or in congruent circles, congruent central angles have ________________________________? That would be, I think, what you could conclude. But, first look up that theorem.

22. OpenSessame

The same measure?