Question

find the area of a triangle two sides of which are 18 cm and 10 cm and the perimeter is 42 CM
$\sqrt{s(s - a)(s - b})(s - c)$

Answer 1

heya friend ✋✋

here's your answer (︶^︶)

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Let , one side of the triangle be x

Given, a =18
b= 10
c = ?
perimeter=42
$= > perimeter = 42cm \\ = > 18 + 10 + x = 42 \\ = > 28 + x = 42 \\ = > x = 42 - 28 \\ = > x = 14$
therefore, c= 14

$semi \: perimeter \: (s) = \frac{42}{2} = 21cm$
$= \sqrt{21(21 - 18)(21 - 10)(21 - 14)} \\ = \sqrt{21 \times 3 \times 11 \times 7} \\ = \sqrt{3 \times 7 \times 3 \times 11 \times 7} \\ = 2 \sqrt{11} \: cm$


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^_^hope it helps u ^_^