Answer:
[tex]\displaystyle 21 \approx c[/tex]
Explanation:
Solving for Angles
[tex]\displaystyle \frac{a^2 + b^2 - c^2}{2ab} = cos\angle{C} \\ \frac{a^2 - b^2 + c^2}{2ac} = cos\angle{B} \\ \frac{-a^2 + b^2 + c^2}{2bc} = cos\angle{A}[/tex]
Do not forget to use [tex]\displaystyle arccos[/tex] or [tex]\displaystyle cos^{-1}[/tex]towards the end, or the result will be thrown off.
Solving for Edges
[tex]\displaystyle b^2 + a^2 - 2ba\:cos\angle{C} = c^2 \\ c^2 + a^2 - 2ca\:cos\angle{B} = b^2 \\ c^2 + b^2 - 2cb\:cos\angle{A} = a^2[/tex]
Take the square root of the result in the end, or you will throw yourself off.
Well, let us get to work:
[tex]\displaystyle 13^2 + 29^2 - 2[13][29]cos\:41 = c^2 \\ 169 + 841 - 754cos\:41 = c^2 \\ 1010 - 754cos\:41 = c^2 \\ \\ \sqrt{440,94897651...} = \sqrt{c^2} \\ 20,99878512... = c \\ \\ \boxed{21 \approx c}[/tex]
I am joyous to assist you at any time.
