## Abbie23 Group Title Find the length of a if the measure of angle A equals 62 degrees b = 15, and c = 21. 2 years ago 2 years ago

1. some1

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2. some1

Do you know if one of the angles are 90 degrees? I mean in the problem, not in the picture i just drew.

3. Abbie23

Idts

4. Cortegu10

i seen this prob before

5. some1

ok then i'm not sure. Because you can use sin, cos, tan only when it's a right triangle. sorry :(

6. Abbie23

It's okay!

7. dpaInc

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8. dpaInc

do you know the law of cosines?

9. AravindG

ya use law of cosines

10. Abbie23

Yes, it's Law of Cosines problem

11. Cortegu10

use law of sine here

12. dpaInc

a^2 = 21^2 + 15^2 - 2*21*15cosA

13. AravindG

$\huge \cos A =\frac{b^2+c^2-a^2}{2bc}$

14. Abbie23

Ok!

15. AravindG

:)

16. AravindG

no rewards?

17. Abbie23

Everyone gets one!

18. AravindG

bt i didnt get any medals :(