Explanation
The first step is to recreate the triangle using the given values.
We can find the value of angle C using the sine rule below.
![\frac{\text{SinB}}{b}=\frac{\text{SinC}}{c}](https://img.qammunity.org/2023/formulas/mathematics/college/g31ck7k3sn529jsws88i27sfkh6foyp329.png)
We insert the necessary parameters.
![\begin{gathered} (Sin42)/(46)=\frac{\text{SinC}}{51} \\ Crossmultiply \\ 46SinC=Sin42*51 \\ SinC=(Sin42*51)/(46) \\ C=\sin ^(-1)0.7419 \\ C=47.9^0 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/mjs88iqmpdx24q2q06i6ef1lw25q6ks3ft.png)
We can find the value of A using the sum of angles in a triangle.
![\begin{gathered} A+B+C=180 \\ A+42+47.9=180 \\ A=180-42-47.9 \\ A=90.1 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/f2ejirqorofcudngy4n95cu85cxmturzt5.png)
We can find the side "a" using the cosine rule
![\begin{gathered} a^2=b^2+c^2-2\text{bc}* CosA \\ a^2=46^2+51^2-2*46*51\text{Cos}90.1 \\ a^2=2116+2601+8.1891 \\ a^2=4725.1891 \\ a^{}=\sqrt[]{4725.1891} \\ a=68.7 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/ufxuo3paxhnxq9vg3iqx8sn0x8aflf6dhs.png)
Answer:
![C=47.9^0;A=90.1^0;a=68.7](https://img.qammunity.org/2023/formulas/mathematics/college/ewzq6iktyvfxn5hbcp6szwo3lga2j7ijz7.png)