Question

Please help geometry. question below

Answer 1

\(\bf \textit{Law of Cosines}\\ \quad \\
a^2 = {\color{blue}{ c}}^2+{\color{red}{ b}}^2-(2{\color{blue}{ c}}{\color{red}{ b}})cos(A)\implies
a = \sqrt{{\color{blue}{ c}}^2+{\color{red}{ b}}^2-(2{\color{blue}{ c}}{\color{red}{ b}})cos(A)}
\\ \quad \\
{\color{blue}{ c}}=23\qquad {\color{red}{ b}}=17\qquad \measuredangle A=42^o
\\ \quad \\

a = \sqrt{{\color{blue}{ 23}}^2+{\color{red}{ 17}}^2-(2\cdot {\color{blue}{ 23}}\cdot {\color{red}{ 17}})cos(42^o)}\)

Answer 2

thank you

Answer 3

so 15.39