Answer
$$A=\frac{43\sqrt{8555}}{4}$$
Work Step by Step
By Heron's Formula, we know:
$$A=\sqrt{s(s-a)(s-b)(s-c)}$$
Where:
$$s=\frac{a+b+c}{2}$$
Thus, we find:
$$s=\frac{51+51+43}{2}=\frac{145}{2} \\ A=\sqrt{\frac{145}{2}\left(\frac{145}{2}-51\right)\left(\frac{145}{2}-51\right)\left(\frac{145}{2}-43\right)} \\ A=\frac{43\sqrt{8555}}{4}$$
