Question

In ∆ABC, if a = 8.75 centimeters, c = 4.26 centimeters, and m B = 87°, What is the length of b to two decimal places?

Answer 1

you will need the law of cosines to solve it

b2=a2+c2−2a×c×cos(B)

just substitute your values

Answer 2

using law cosines:
b^2= a^2+c^2-2acCosb
= 76.56+18.14-74.55(0.05)
= 94.7 - 3.9
= 90.8
b= sqrt 90.8
b= 9.52