Using the coordinate geometry formula, the exact area of triangle DEF is: B. 18 square units.
What is the Coordinate Geometry Formula?
The coordinate geometry formula is used to find the rea of a triangle with given coordinates of its vertices. It is given as: the absolute value of [Dx(Ey - Fy) + Ex(Fy - Dy) + Fx(Dy - Ey)]/2.
Dx = -3
Dy = 4
Ex = 3
Ey =-2
Fx = 3
Fy = 4
Plug in the values:
[-3(-2 - 4) + 3(4 - 4) + 3(4 - (-2))]/2.
[-3(-6) + 3(0) + 3(6)]/2.
[18 + 0 + 18]/2.
36/2
= 18 units²
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