Resposta :
A medida do lado AB:
[tex]\boxed{d_{AB}=\sqrt{(3-1)^2+(-1-2)^2}=\sqrt{2^2+(-3)^2}=\sqrt{4+9}=\sqrt{13}}[/tex]
Area do triângulo:
| 1 2 1 |
A=1/2. | 3 -1 1 |
| 2 4 1 |
A=1/2.(-1+4+12+2-6-4)=1/2.7=7/2
[tex]\boxed{d_{AB}=\sqrt{(3-1)^2+(-1-2)^2}=\sqrt{2^2+(-3)^2}=\sqrt{4+9}=\sqrt{13}}[/tex]
Area do triângulo:
| 1 2 1 |
A=1/2. | 3 -1 1 |
| 2 4 1 |
A=1/2.(-1+4+12+2-6-4)=1/2.7=7/2