You can use the formula \(A = \sqrt{s(s-a)(s-b)(s-c)}\) to solve this. The s variable represents the semiperimeter which is: 2 + 5 + 6 = 13 , half of that is 7.5.
\(A = \sqrt{7.5(7.5-2)(7.5-5)(7.5-6)} = \sqrt{7.5\times20.625} = \sqrt{154.6875} = \boxed{\frac{15}{4}\sqrt{11}}\)
