Question

What is the area of a triangle whose vertices are D(3, 3) , E(3, −1) , and F(−2, −5) ?

Answer 1

We are given vertices of the triangle DEF as:

D(3, 3) , E(3, −1) , and F(−2, −5) .

Let us plot those points on the graph.

Formula of area of the triangle with vertices (x1,y1), (x2,y2) and (x3,y3).

Area = 1/2 [ (x2-x1)(y3-y1)-(x3-x1)(y2-y1)]

We have x1=3, x2=3, x3=-2, y1=3, y2 =-1 and y3 = -5.

Plugging values in formula, we get

Area = |1/2 [ 3-3)(-5-3)-(-2-3)(-1-3)]|

= |1/2 [ 0(-8) - (-5)(-4)]|

=| 1/2 [0 - 20]|

= |-10|

=10.

Therefore, area of the triangle with given vertices is 10 square units.