Question

The sides of a triangle are 3 cm, 5 cm and 6 cm. What is its area?
a. 2√3cm2
b. 4√14cm2
c. 5√12cm2
d. 2√5cm2

Answer 1

but this is nat in choice

Answer 2

$Let \: a, b \:and \: c \: are \: three \:sides \:of \:a \: triangle$

$a = 3 \:cm , \: b = 5 \:cm \:and \: c = 6 \:cm \:(given)$

$s = \frac{a+b+c}{2} \\= \frac{3+5+6}{2}\\= \frac{14}{2} \\= 7$

$Area \: of \:the \: triangle \\= \sqrt{s(s-a)(s-b)(s-c)} \\= \sqrt{7(7-3)(7-5)(7-6)} \\= \sqrt{ 7\times 4 \times 2 \times 1 }\\= 2\sqrt{14} \:cm^{2}$

Therefore.,

$\red{Area \: of \:the \: triangle}\green {= 2\sqrt{14} \:cm^{2}}$

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