Question

What is the length of side c, given a = 10, b = 8, and c = 105°?

Answer 1

We can calculate using cosinus method in triangle
c² = a² + b² - 2ab cos c

Plug in the number to the formula
c² = a² + b² - 2ab cos c
c² = 10² + 8² - 2(10)(8) cos 105°
c² = 100 + 64 - 160 cos 105°
c² = 164 - 160 (-0.26)
c² = 164 + 41.6
c² = 205.6
c = √205.6
c =14.34

C is 14.34 unit length