## TNNG Group Title Solve the triangle. B = 36°, a = 41, c = 20 one year ago one year ago

1. TNNG Group Title

b ≈ 27.5, C ≈ 115.5, A ≈ 28.5 b ≈ 45.3, C ≈ 25.5, A ≈ 118.5 b ≈ 45.3, C ≈ 29.5, A ≈ 114.5 b ≈ 27.5, C ≈ 25.5, A ≈ 118.5

2. terenzreignz Group Title

Law of Cosines?

3. geerky42 Group Title

Yes.

4. terenzreignz Group Title

You arrived at a solution, @TNNG ?

5. geerky42 Group Title

Use law of cosines to find b then use law of sines to find the rest of angles.

6. TNNG Group Title

ok so just use to law of cosines and i should get the answer

7. geerky42 Group Title

Well, you're not finished, since you still have to find A and C so use law of sines for this.

8. TNNG Group Title

i don't get it i got the D for my answer is that correct

9. geerky42 Group Title

What don't you get?

10. TNNG Group Title

the law of sines

11. geerky42 Group Title

The Law of Sines: $$\Large \dfrac{\sin A}{a} =\dfrac{\sin B}{b} =\dfrac{\sin C}{c}$$

12. geerky42 Group Title

Familiar with it?

13. TNNG Group Title

i know that but i don't get how to plug it is plus i tried it again and got Choice B

14. terenzreignz Group Title

Well, you could certainly use the law of Cosines to arrive at all the other missing parts of the triangle, but that's really cumbersome, compared to the simpler looking law of sines.

15. geerky42 Group Title

Yeah, it's only way to find the b. You just have to use it once, then use law of sines and you're good to go. You don't have to use entire formula, just use part of it, like $$\dfrac{\sin B}{b} = \dfrac{\sin C}{c}$$ Is this clear?

16. geerky42 Group Title

The law of tangents is really cumbersome compared to the law of cosines :P

17. TNNG Group Title

ok so i know b=27.5

18. geerky42 Group Title

Yes.

19. TNNG Group Title

so figure out that a = 28.5

20. geerky42 Group Title

No, no, you already have the given value of a, so just use law of sines to find the angle.

21. geerky42 Group Title

Now you know a, b, c, and B. Now all you need to do is find A and C.

22. TNNG Group Title

is the angle 25.5

23. geerky42 Group Title

None, not what I get.

24. TNNG Group Title

115.5

25. pooja195 Group Title

b^2 = a^2 + c^2 - 2accosB b = 27.5

26. geerky42 Group Title

Wait, you're right, angle C is close to 25.5º. My bad. Now find the other angle.

27. geerky42 Group Title

180º - (A + C) = B

28. TNNG Group Title

118.5

29. TNNG Group Title

so i had it right the first time

30. geerky42 Group Title

Yes! Is this clear?

31. geerky42 Group Title

You have to do math, though. You can't just guess. Just saying.