Question

The edges of a triangular board are 6 cm, 8cm and 10cm . The cost of painting it at the rate of 9 paise per cm^2 is

Answer 1

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$s = \frac{6 + 8 + 10}{2} = \frac{24}{2} = 12cm \\ \\ area \: = \sqrt{12(12 - 6)(12 - 8)(12 - 10)} \\ (by \: heron \: formula) \\ \\ = > \sqrt{12 \times 6 \times 4 \times 2} \\ \\ = > \sqrt{(6 \times 2) \times 6 \times 4 \times 2} \\ \\ = > (6 \times 2 \times 2)c {m}^{2} \\ \\ = > 24 \: c {m}^{2} \\ \\ cost \: \: of \: painting \: \: = rs. \: (24 \times 0.09) \\ \\ answer \: \: = rs. \: 2.16 \:$
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