Heron's formula is given as
[tex]A\text{ =}\sqrt[]{s(s-a)(s-b)(s-c)}[/tex]and
[tex]s\text{ =}\frac{1}{2}(a+b+c)[/tex]we are given that
[tex]a=6.2,\text{ b = 7.5 and c = 4.9}[/tex]First, we find the value of s using the formula
[tex]\begin{gathered} s\text{ = }\frac{1}{2}(6.2\text{ + 7.5 + 4.9)} \\ s\text{ = }\frac{18.6}{2} \\ s\text{ = 9.3} \end{gathered}[/tex]next, we substitute values of a, b, c, and s to get the area
[tex]\begin{gathered} A\text{ = }\sqrt[]{s(s-a)(s-b)(s-c)} \\ A\text{ = }\sqrt[]{9.3(9.3-\text{ 6.2)(9.3 - 7.5)(9.3 - 4.9) }} \\ A\text{ = }\sqrt[]{9.3\text{ }\times3.1\times\text{ 1.8 }\times\text{ 4.4}} \\ A\text{ = }\sqrt[]{228.33} \\ A\text{ = 15.1 square units} \end{gathered}[/tex]Therefore,
Area of triangle = 15.1 square units