Answer:
12
Step-by-step explanation:
1) Vector AB (-2-(-6); -1-(-1))= (4; 0). Vector module is module AB=sqrt (4*4+0*0)= 4
2) The module of Vector BC is sqrt((-1-(-2))*(-1 - (-2))+ (-4-(-1))* (-4-(-1))= sqrt (9+1)= sqrt 10.
3) The module of AC is sqrt ((-1-(-6))*(-1-(-6))+ (-4-(-1))*(-4-(-1))= sqrt (25+9)= sqrt 34.
4) Having the triangle with the sides AB, BC, AC use the theorem of cos:
sqrt34*sqrt34= sqrt 10*sqrt 10 + 4*4- 2*sqrt10*4*cosB
34-10-16= -8 sqrt 10*cosB
c0sB= (-1)/ sqrt10
5) Find out sinB that is equal to Sqrt (1- ((-1)/sqrt 10)* ((-1)/sqrt10))= sqrt (9/10)= 3/sqrt10.
6)S= 4*sqrt10*3/sqrt10= 4*3=12. The area is equal to 12.