Question

Find the area of the triangle whose vertices are A(-2,-3) B(3
,20) and C(-1,-8)?

Answer 1

Area of triangle with vertices (x1,y1), (X2, y2), (X3, y3)

={ (X1 (Y2-Y3)+X2 (Y3-Y1)+X3(Y1-Y2) }. /2

Hence:- (X1,Y1)= (-2,-3)

( X2,Y2)=(3,20)

(X3,Y3)=(-1,-8)

we get,

{-2(20-(-8))+3(-8-(-3))+(-1)(-3-20)} /2

{-2(20+8)+3(-8+3)-1(-3-20)} /2

{-2(28)+3(-5)-1(-23)}. /2

{-56-15+20} /2

{-71+23} /2

{-48} /2

-24

so the area of triangle is -24