Question

Answer this question please

Answer 1

$\:\: \underline{\underline{\bf{\large\mathfrak\red{~~Solution~~}}}}$

the there sides are 18cm,12cm, and

(40-(12+18))=10 cm

now the half of the perimeter=40/2=20 cm

therefore area....

$\sqrt{20(20 - 18)(20 - 12)(20 - 10)} cm {}^{2} \\ = \sqrt{20 \times 2 \times 8 \times 10} \\ = 10 \times 4 \sqrt{2} \\ = 40 \sqrt{2} \: cm {}^{2}$

$:\: \underline{\underline{\bf{\large\mathfrak{~hope ~this ~help~you~~}}}}$

Answer 2

$\huge\underline\purple{\sf Answer:-}$

$\large{\boxed{\sf Area\:of\: triangle=56.56{cm}^{2}}}$

$\huge\underline\purple{\sf Solution:-}$

★Given :-

First side (a) = 18 cm

Second side (b) = 12cm

Third side (c)= ?

Perimeter of triangle = 40 cm

$\large{\boxed{\sf Perimeter\:Of\: Triangle=a+b+c}}$

On Putting value :-

$\large\implies{\sf 40=18+13+c}$

$\large\implies{\sf c =40-30}$

$\large\implies{\sf c =10cm}$

Also ,

$\large{\boxed{\sf s ={\frac{a+b+c}{2}}}}$

$\large\implies{\sf {\frac{40}{2}}}$

$\large\implies{\sf s =20}$

By Heron's Formula :-

$\large{\boxed{\sf Area\:Of\:triangle(A)={\sqrt {s(s-a)(s-b)(s-c)}}}}$

$\large{\sf A ={\sqrt{20(20-18)(20-12)(20-10)}}}$

$\large{\sf A={\sqrt{20×2×8×10}}}$

$\large{\sf A=40{\sqrt{2}}}$

We know that :-

$\large{\sf \sqrt{2}=1.414}$

$\large{\sf A = 56.56{cm}^{2}}$

★$\large\red{\boxed{\sf A=56.56{cm}^{2}}}$