Question

The difference of semi-perimeter and the sides of △ABC are 8cm, 7cm and 5 cm respectively. Its semi-perimeter ‘s’ is​

Answer 1

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The difference of semi-perimeter and the sides of △ABC are 8cm, 7cm and 5 cm respectively. Its semi-perimeter ‘s’ is ?

Suppose :-

_________

Let's the sides of the triangle be a,b and c and the semi perimeter( S) =

$\t\frac{a + b + c}{2}$

GIVEN :-

_______

S - à = 8 CM

S - b = 7 cm

S - c = 5 cm

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To Find :-

________

➩ 3S - ( a+b+c) = 20 CM

➩ 3S - 2S = 20 CM

➩ S = 20 CM

So , Area of ∆ =

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

=

$\sqrt{20 \times 8 \times 7 \times 5 \: cm {?}^{2} }$

= 20

$\sqrt{14 \: cm {}^{2} }$

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