Brainliest answer to first ! select the angle that correctly completes the law of cosines for this triangle. 12^2+13^2-2(12)(13)cos__=5^2 answers in pic.

Option B is correct i.e,

Explanation:

Law of cosine is useful to find:

* The third side of a triangle when we know two sides and angle between them.

* The angles of a triangle when we know all three sides.

It can be either of these forms;

Given triangle ABC is right angle triangle.

Law of cosines for this triangle is,

since, , and .

then,

1. 3.4/4

2. 0.8/7

3. 0.5 x 3

4. 0.9 x 6

5. 10.8

6. 2.35

7. 0.567

8. 9.35

9. 0.02

10. 0.06

11. 0.16

12. 0.42

13. 0.63

14. 5.6

15. 8.1

16. 9.9

17. 0.28

18. 0.48

19. 0.27

20. 0.49

21. 0.45

22. 0.72

23. 0.9

24. 0.88

25. 0.75

26. 0.16

27. 0.328

28. 0.495

29. 0.72

30. 1.068

a is 8.b is 10.c is 10.5. d is -.5

step-by-step explanation:

just minus the smallest number from the biggest.