Given the triangle below, what is m B, rounded to the nearest tenth?

82.8

Step-by-step explanation:

LAW OF COSINES

b^2 = a^2 + c^2 − 2ac cos(b)                formula

12^2 = 10^2 + 8^2 - 2(10)(8) cos (b)       substitute and calculate

144 = 100 + 64 - 160 cos (b)                  add like terms

144 = 164-160 cos (b)                             subtract 164

- 20 = -160 cos (b)                                  divide by -160/reduce  

1/8 = cos (b)                                            inverse cos each side

b = 82.8

1/8 is left? add a bit more info plz