Bantu jawab donk plisss.... Question from @raffasatria2021

Jika sebuah segitiga hanya diketahui panjang sisi-sisinya, maka luas segitiga tersebut bisa dihitung dengan rumus : $\boxed{\boxed{\purple{\sf L=\sqrt{s\times (s-a)\times (s-b)\times (s-c)}}}}$ , dimana : $\boxed{\boxed{\purple{\sf s=\frac{1}{2}\times (a+b+c)}}}$

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$\huge{\green{1~)}}$

$\huge{\red{\sf Keliling~:}}$

$\sf =7+10+12=\red{\huge{29~cm}}$

$\huge{\red{\sf Luas~:}}$

$\sf s=\frac{1}{2}\times 29=\frac{29}{2}$

$\sf L=\sqrt{\frac{29}{2}\times \left(\frac{29}{2}-7\right)\times \left(\frac{29}{2}-10\right)\times \left(\frac{29}{2}-12\right)}$

$\sf =\sqrt{\frac{29}{2}\times \left(\frac{15}{2}\right)\times \left(\frac{9}{2}\right)\times \left(\frac{5}{2}\right)}$

$\sf =\sqrt{\frac{19.575}{16}}=\sqrt{\frac{225\times 87}{16}}$

$\sf =\red{\huge{\frac{15}{4}\sqrt{87}~cm^2}}$

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$\sf alas=2\times \left(\sqrt{14^2-11^2}\right)$ $\sf =2\times \left(\sqrt{196-121}\right)$ $\sf =2\times \left(\sqrt{75}\right)$ $\sf =2\times \left(\sqrt{25\times 3}\right)$ $\sf =2\times \left(5\sqrt{3}\right)$ $\sf =10\sqrt{3}~cm$