Question

Find angle C in degrees.Round to the nearest tenth.Сa = 11bb = 12A C= 20аBСC = [?]

Answer 1

120.8degrees

Step-by-step explanation:

To get the angle C, we will use the cosine rule formula as shown;

`c^2=a^2+b^2-2ab\cos C`

Given the following;

a = 11

b = 12

c = 20

Substitute into the formula above;

`\begin{gathered} 20^2=11^2+12^2-2(11)(12)\cos C \\ 400\text{ = 121 + 144 - }264\cos C \\ 400\text{ = }265-264\cos C \\ 400\text{ - 265 = -264cosC} \\ 135\text{ = -2}64\cos C \\ \text{CosC = -}(135)/(264) \\ \text{CosC =-}0.5114 \\ C=cos^(-1)(-0.5114) \\ C\text{ =}120.75 \\ C\approx120.8^0 \end{gathered}`

Hence the measure of mes