Someone please help me with this question i really need help

b = 7.76

Step-by-step explanation:

ABC is a triangle. In a triangle, we have the formula as following:

+) Cosine ∠An angle =

As we can see in the figure, Angle B has:

+) Adjacent side a is BA = 10

+) Adjacent side b is BC = 12

+) Opposite side is AC = b

The measure of Angle B is 40°.

Replace these into the formula, we have:

+) Cosine ∠B =

⇔ Cosine 40° =

⇔ 0.766 =

⇔ 0.766 x 240 = 244- b^2

⇔ 183.84 = 244 -b^2

⇔ b^2 = 244 - 183.84 = 60.16

⇔ b = = 7.76

the answer to the expression is 83