Law of cosines: a2 = b2 + c2 – 2bccos(A)

Which equation correctly uses the law of cosines to solve for the missing side length of PQR?

62 = p2 + 82 – 2(p)(8)cos(39°)
p2 = 62 + 82 – 2(6)(8)cos(39°)
82 = 62 + p2 – 2(6)(p)cos(39°)
p2 = 62 + 62 – 2(6)(6)cos(39°)

Law of cosines a2 b2 c2 2bccosA Which equation correctly uses the law of cosines to solve for the missing side length of PQR 62 p2 82 2p8cos39 p2 62 82 268cos3 class=