Question

. find the area of triangle whese vexetics are 1 1) (3, 1), (1, 3), 8 (-3,-2) el 4​

Answer 1

(3,1) = (x1,y1)

(1,3) = (x2, y2)

(-3,-2) = (x3,y3)

• Solving it by Determinant Method

│x1 y1 1 │

= ½ │x2 y2 1 │

│x3 y3 1 │

│3 1 1 │

= ½ │1 3 1 │

│-3 -2 1 │

= ½ [ 3(3 + 2) - 1(1 + 3) + 1(-2 + 9)]

= ½[3(5) - 4 + 7]

= ½(15 + 3)

= ½(18)

= 9 unit² is area