Question

Find angles please please

Answer 1

Law of Cosines is what you need for this problem
To find ∡A: 21² = 12² + 29² - 2(12)(29)cos A
When you solve this equation you get m∡A ≈ 38.6°

To find ∡B: 12² = 21² + 29² -2(21)(29)cos B
When you solve this equation you get m∡B ≈ 20.9°

To find ∡C: 180° - (20.9° + 38.6°) = 120.5°

Answer 2

You have to use the Law of Cosines twice here. Let's find angle A first:
`21^(2)= (12)^(2)+(29) ^(2) -2(12)(29)cosA`. Doing a bit of simplifying you get
`441=144+841-696cosA`. Simplifying a bit more gives you -544=-696cosA. cosA = .78160919 and that A = 38.6. Actually, now that I think about it we can now move to the Law of Sines to find another angle because the triangle is not a right triangle. Just trust me. Let's find angle B now.
`(sinB)/(12)= (sin38.6)/(21)` and that
`sinB= (12sin38.6)/(21)`. sinB = .3565026267 and that angle B is 20.9. Knowing those 2 angles we can find C: 180-38.6-20.9=120.5 and there you have it.