Question

Help me please!

a = 3, b = 5, and c = 7. What is m&Bº to the nearest tenth?

Answer 1

Answer: m∡B°=38,2°.

Explanation:

a=3, b=5, c=7 ∡B°=?

`b^2=a^2+c^2-2*a*ccosB^0\\2*a*c*cosB^0=a^2+c^2-b^2\\cosB^0=(a^2+c^2-b^2)/(2*a*c) \\cosB^0=(3^2+7^2-5^2)/(2*3*7) \\cosB^0=(9+49-25)/(2*3*7) \\cosB^0=(33)/(42) \\cosB^0=(11)/(14)\\`

m∡B°=arccos
`((11)/(14))`

m∡B°≈38,2°.

Good luck!