Question

the area of a quadrilateral with vertices (2,-1),(4,3),(-3,-2) is
a)54 sq
b)36 sq
c)18 sq
d)20sq

Answer 1

A quadrilateral has 4 sides and you have given only 3 coordinates. So post again

Answer 2

ABCD is a quadrilateral .
Area of quadrilateral ABCD = are(triangle ABC) + ar( triangle ACD) .

For triangle ABC , we have

X1 = 2 , X2 = 4 , X3 = -3 ,Y1 = -1 , Y2 = 3 ,Y3 = -2.

Therefore,

Ar( ABC ) = 1/2[ X1(Y2-Y1) + X2( Y3-Y1)+X3(Y1-Y2).
PUT VALUES AND FIND THE AREA OF TRIANGLE ABC .

SIMILARLY
FIND THE AREA OF TRIANGLE ACD.

AND THEIR AREA...U WILL GET THE ANSWER.