Question

Sides of a triangle are 45cm,39cm,and 42cm ,find its area​

Answer 1

Answer:

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Area of a triangle of 45 and 39 is 877.5..

I mean 45 as base and 39 as height..

Area of triangle of 45 and 42 is 945..

I mean 45 as base and 42 as height..

Area of triangle of 42 and 39 is 819..

I mean 42 as base and 39 as height..

Area of triangle of 45,42and 39 is 756...

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Answer 2

Given

• Sides of triangle are a = 45cm. , B = 39cm, c = 42cm

Formula needed to use

$\sf \: semiperimeter = \dfrac{a + b + c}{2}$

Solution

$\sf \: \implies \: \dfrac{a + b + c}{2}$

$\implies \sf \: \dfrac{45 + 39 + 42}{2}$

$\sf \implies \: \cancel \dfrac{ 126 }{ 2}$

$\sf \implies \dfrac{63}{1}$

By heron's formula

$\sf \implies \sqrt{s(s - a)(s - b)(s - c)}$

$\sf \: \implies \: \sqrt{63(63 - 45)(63 - 39)(63 - 42)}$

$\sf \implies\sqrt{63 \times 18 \times 24 \times 21}$

$\sf \implies \sqrt{7 \times 9 \times 9 \times 2 \times 4 \times 6 \times 3 \times 7}$

$\sf \implies\sqrt{7 \times 9 \times 2 \times 2 \times 2 \times 3 \times 3 \times 2}$

$\sf\implies7 \times 9 \times 2 \times 2 \times 3$

$\sf\implies63 \times 4 \times 3$

$\sf\implies {756cm}^{2}$