Question

find the area of a triangle two sides of which are 15 cm and 28 cm and the perimeter 84cm​

Answer 1

Answer:

126cm²

Step-by-step explanation:

I hope that you are able to understand.

Answer 2

$\sf{\bold{\green{\underline{\underline{Given}}}}}$

• Two sides of triangle = 15cm and 28cm
• Perimeter = 84cm

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$\sf{\bold{\green{\underline{\underline{To\:Find}}}}}$

• Area = ??

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$\sf{\bold{\green{\underline{\underline{Solution}}}}}$

$\sf{\red{\boxed{\bold{perimeter = A + B + C}}}}$

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$\sf: \implies{\bold{84 = 15 + 28 + c}}$

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$\sf: \implies{\bold{ 84 = 43 + c}}$

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$\sf: \implies{\bold{ c = 84 - 43}}$

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$\sf: \implies{\bold{ c = 41 }}$

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$\sf{\red{\boxed{\bold{Semi\: Perimeter = \dfrac{perimeter}{2}}}}}$

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$\sf: \implies{\bold{ Semi\: Perimeter = \dfrac{84}{2}}}$

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$\sf: \implies{\bold{Semi\: perimeter = 42}}$

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$\sf{\red{\boxed{\bold{area =\sqrt{ s ( s - a )( s - b)( s - c )}}}}}$

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$\sf: \implies{\bold{area =\sqrt{ 42( 42 - 41)( 42 - 15)( 42 - 28)}}}$

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$\sf: \implies{\bold{area =\sqrt{ 42 \times 1 \times 27 \times 14}}}$

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$\sf: \implies{\bold{area =\sqrt{ 2\times 3\times 7\times 1 \times 3 \times 3 \times 3 \times 2 \times 7 }}}$

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$\sf: \implies{\bold{ area = 2 \times 3\times 3 \times 7}}$

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$\sf: \implies{\bold{area = 18 \times 7}}$

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$\sf: \implies{\bold{area = 126 cm^2}}$

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$\sf{\bold{\green{\underline{\underline{Answer}}}}}$

• Therefore the area of triangle is 126cm^2