1.
[tex]MN=\sqrt{(12-5)^2+(8-8)^2}=\sqrt{49} =7\\\\\\MP=\sqrt{(-4-5)^2+(4+8)^2}=\sqrt{81+144}=15\\\\ NP=\sqrt{(-4-12)^2+(4+8)^2} =\sqrt{256+144}=20\\\\ p=\frac{7+15+20}{2} = 21\\\\A=\sqrt{21(21-7)(21-15)(21-20)} =\sqrt{21\times 14\times 6\times1}= 7\times6=42cm^2[/tex]
2.
[tex]AB=\sqrt{(12-8)^2+(12-16)^2}=\sqrt{16+16} =4\sqrt{2} \\\\BC=\sqrt{(0-12)^2+(4-12)^2} =\sqrt{144+64}=\sqrt{208} =4\sqrt{13} \\\\AC=\sqrt{(0-8)^2+(4-16)^2} =\sqrt{64+144} =4\sqrt{13}[/tex]
Avem BC=AC⇒ΔABC isoscel
