[tex]p = \frac{a + b + c}{2} = \frac{6 + 9 + 11}{2} = \frac{15 + 11}{2} = \frac{26}{2} = 13 [/tex]
[tex]A = \sqrt{p(p - a)(p - b)(p - c)} = \sqrt{13(13 - 6)(13 - 9)(13 - 11)} = \sqrt{13 \times 7 \times 4 \times 2} = \sqrt{91 \times 4 \times 2} = \sqrt{364 \times 2} = \sqrt{728} = 2 \sqrt{182} \: \: {m}^{2} \\ \\ \sqrt{728} = \sqrt{2 \times 2 \times 2 \times 7 \times 13} = \sqrt{(2 \times 2) \times 2 \times 7 \times 13} = \sqrt{ {2}^{2} \times 2 \times 7 \times 13 } = 2 \sqrt{2 \times 7 \times 13} = 2 \sqrt{182} [/tex]
